Middle School Science Quiz: Molecules Support Growth

20 questions · exam conditions

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Molecules Support GrowthQuestion 1 of 20

A simplified model shows a caterpillar growing after eating. Before: small molecules are shown inside the caterpillar. The model shows these small molecules being rearranged and connected into larger structures in the body. After: the caterpillar has more body tissue, and the larger structures are now part of the new tissue. The model includes the statement: "Rearranged molecules support growth and repair."

Which set of statements is supported by the model? (Choose the best option.)

Growth is only an increase in size; the molecules inside do not need to change as long as the organism looks bigger.

Small molecules inside the organism can be rearranged into larger structures; those larger structures become part of new tissue; growth and repair require matter input over time.

Molecules are used once and then disappear; the organism grows mainly because energy turns into matter.

The model proves exactly what every molecule looks like in real life, so the shapes in the picture must be copied perfectly.

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Middle School Science Quiz

Middle School Science Quiz: Molecules Support Growth

Practice Molecules Support Growth in Middle School Science with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Molecules Support Growth, giving you a quick way to practice the rules, question types, and explanations that matter most for Middle School Science.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

Which set of statements is supported by the model? (Choose the best option.)

Growth is only an increase in size; the molecules inside do not need to change as long as the organism looks bigger.
Small molecules inside the organism can be rearranged into larger structures; those larger structures become part of new tissue; growth and repair require matter input over time. (correct answer)
Molecules are used once and then disappear; the organism grows mainly because energy turns into matter.
The model proves exactly what every molecule looks like in real life, so the shapes in the picture must be copied perfectly.

Explanation: The core skill is understanding how molecules support the growth and repair of living organisms, such as a caterpillar increasing in size after eating. Small molecules inside the caterpillar, derived from food, are rearranged and connected to form larger molecules that add to its body tissues. Models represent this by illustrating small molecules as dots that are linked into chains or blocks, showing tissue expansion in before-and-after comparisons. To check your understanding, evaluate if the model supports statements about molecular rearrangement rather than energy-to-matter conversion. A common misconception is that molecules disappear after use, but they are actually rearranged into persistent larger structures. Because matter is conserved, atoms from food molecules are preserved in the new tissues without creation or loss. This conserved matter enables insects like caterpillars to achieve growth and repair efficiently.

Question 2

A model of a growing puppy shows many small molecules inside the puppy. Arrows show small molecules being connected into larger structures in muscles and bones. Before: fewer larger structures are shown. After: more larger structures are shown as part of new tissue. The model includes the sentence: "Rearranged molecules support growth and repair."

Which prediction is supported by the model if the puppy does not get enough small molecules from its surroundings (for example, not enough food/water molecules entering the body)?

Growth and repair will slow down because there are fewer small molecules available to rearrange into the larger structures that make new tissue. (correct answer)
The puppy will still grow normally because growth happens without input of molecules; time alone causes new tissue to appear.
Growth will speed up because the body will create new matter to replace missing molecules.
The puppy will grow normally because the body can reuse the same small molecules forever without needing any new ones.

Explanation: The core skill is understanding how molecules support the growth and repair of living organisms, such as a puppy developing muscles and bones. Small molecules inside the puppy, sourced from food and water, are rearranged and linked to form larger molecules that contribute to new tissues in growing areas. Models illustrate this by depicting small molecules as dots that are assembled into chains or structures, with arrows showing their integration into muscles and bones. To check your understanding, predict outcomes like slowed growth if molecule input decreases, and compare with the model's before-and-after depictions. A common misconception is that growth continues normally without new molecules, but it actually requires ongoing input to rearrange into tissues. Since matter is conserved, the atoms from ingested small molecules become part of the larger structures without disappearance or creation. This conserved matter principle enables animals like puppies to sustain growth and repair over time.

Question 3

A model shows a child's broken bone repairing. Before: the bone is cracked, and small molecules are shown inside the body. The model shows small molecules being assembled into larger structures at the crack. After: the crack is filled in with new bone tissue. The model includes: "Rearranged molecules support growth and repair."

Which evidence from the model best supports the idea that matter is conserved during repair (matter does not appear from nowhere or disappear)?

The model shows the bone looks smoother after repair, so it must have gained matter.
The model shows small molecules already inside the body being connected into larger structures that become part of the repaired bone. (correct answer)
The model shows the crack disappears, so the matter from the crack must have vanished.
The model shows that repair happens because healing energy fills the crack without using molecules.

Explanation: The core skill is understanding how molecules support the growth and repair of living organisms, such as a child's bone healing after a break. Small molecules inside the body are rearranged and assembled into larger molecules that fill in and strengthen the cracked bone tissue. Models depict this by showing small molecules as dots being connected into larger structures at the fracture site, with before-and-after views highlighting the repair. To check your understanding, look for evidence in the model that matter is neither created nor destroyed, such as consistent molecule counts during assembly. A common misconception is that matter vanishes or appears during repair, but it is actually conserved through rearrangement into new forms. Since matter is conserved, the atoms in small molecules become integral to the larger bone structures without any net change in matter. This principle allows the body to support effective growth and repair in bones and other tissues.

Question 4

A simplified model shows a starfish regrowing an arm. Before: the arm is missing, and small molecules are shown inside the starfish. The model shows these small molecules moving to the missing-arm area and being connected into larger structures. After: a new arm is present and contains the larger structures. The model states: "Rearranged molecules support growth and repair."

Which evidence-based explanation is best supported by the model?

The new arm forms because small molecules inside the starfish are rearranged and assembled into larger structures that become the new arm tissue. (correct answer)
The new arm forms because the starfish remembers the shape of an arm, so the arm appears without needing molecules to build it.
The new arm forms because the small molecules are used once and then disappear, so they cannot be part of the new tissue.
The new arm forms because the model's connected dots randomly stick together without any relation to growth or repair.

Explanation: The core skill is understanding how molecules support the growth and repair of living organisms, such as a starfish regenerating a lost arm. Small molecules inside the starfish are rearranged and assembled into larger molecules that form the new arm tissue. Models depict this by showing small molecules as dots moving and connecting into bigger structures at the regeneration site, with before-and-after comparisons. To check your understanding, evaluate explanations against the model to ensure they highlight molecular assembly as evidence. A common misconception is that regeneration occurs without molecules, like through memory or random sticking, but it requires purposeful rearrangement. Since matter is conserved, atoms from small molecules are preserved in the larger structures of the new arm. This principle of conserved matter enables remarkable repair and growth in organisms like starfish.

Question 5

A model shows a young tree closing a small wound in its bark. In the before panel, small molecules are shown inside the tree near the wound. Arrows show the small molecules being assembled into larger structures that fill the wound. In the after panel, the wound is covered by new bark tissue. The model states: "Rearranged molecules support growth and repair."

Which prediction about growth and repair is supported if the tree has fewer small molecules available near the wound?

The wound would likely close more slowly or less completely because fewer small molecules could be assembled into the larger structures needed for new bark tissue. (correct answer)
The wound would close the same because growth and repair do not require molecules as building materials.
The wound would close the same because the tree can make new bark by creating new matter inside the wound area.
The wound would close faster because having fewer molecules means the molecules can assemble more randomly and quickly.

Explanation: The core concept in middle school life science is that molecules support the growth and repair of living organisms by providing the building blocks for new tissues. Small molecules, such as those from food, are rearranged inside the body to form the complex structures needed for healing processes like closing a wound in a tree's bark. Models demonstrate this by using arrows to illustrate how small molecule pieces are connected into longer chains and stacked layers that fill in wounds. To check your understanding, count the small molecules in the before panel and ensure they match the components in the larger structures of the after panel, confirming no matter is created or destroyed. A common misconception is that repair can happen without molecules as building materials, but they are essential. Conserved matter ensures that organisms can repair efficiently without needing to produce matter anew. This principle of matter conservation supports both growth and repair across all living things, allowing for sustainable development and recovery.

Question 6

A model shows a young bird growing. In the before panel, small molecules are shown inside the bird's body. Arrows show these small molecules being linked and packed into thicker structures in the wing. In the after panel, the wing has more tissue than before. The model states: "Rearranged molecules support growth and repair."

Which evidence from the model supports the idea that growth happens by rearranging molecules into larger structures (not just getting bigger in size)?

The model uses arrows to show small molecules being assembled into larger structures that become additional wing tissue. (correct answer)
The after panel shows a bigger-looking wing, so growth must mean size increased even if molecules did not change.
The model label is enough to prove growth, even without showing molecules being connected.
The bird can grow without any input of molecules because bodies can create new matter during growth.

Explanation: The core concept in middle school life science is that molecules support the growth and repair of living organisms by providing the building blocks for new tissues. Small molecules, such as those from food, are rearranged inside the body to form the complex structures needed for processes like wing growth in a young bird. Models demonstrate this by using arrows to illustrate how small molecule pieces are connected into longer chains and stacked layers that add tissue and enable expansion. To check your understanding, count the small molecules in the before panel and ensure they match the components in the larger structures of the after panel, confirming no matter is created or destroyed. A common misconception is that growth is just about increasing size without molecular changes, but actually, it involves building new structures from rearranged molecules. Conserved matter ensures that organisms can grow efficiently without needing to produce matter anew. This principle of matter conservation supports both growth and repair across all living things, allowing for sustainable development and recovery.

Question 7

A model shows a mouse growing new fur after a bald patch. In the before panel, small molecules are shown inside the mouse under the skin. Arrows show small molecules being assembled into larger structures that form a new layer in the skin. In the after panel, the bald patch is covered. The model states: "Rearranged molecules support growth and repair."

Which supported statement best explains what happens to molecules during this repair?

Small molecules are rearranged into larger structures that become part of new skin and fur, so matter is reused in the body. (correct answer)
The molecules in the model are only labels to memorize; they do not represent real matter in the mouse.
The molecules are not part of the repair; the body heals because energy alone fills in the bald patch.
Repair happens because the mouse's skin stretches to cover the patch, so no new structures are built.

Explanation: The core concept in middle school life science is that molecules support the growth and repair of living organisms by providing the building blocks for new tissues. Small molecules, such as those from food, are rearranged inside the body to form the complex structures needed for processes like growing new fur in a mouse. Models demonstrate this by using arrows to illustrate how small molecule pieces are connected into longer chains and stacked layers that add tissue and enable recovery. To check your understanding, count the small molecules in the before panel and ensure they match the components in the larger structures of the after panel, confirming no matter is created or destroyed. A common misconception is that energy alone can heal without molecules, but actually, molecules are essential building pieces. Conserved matter ensures that organisms can repair efficiently without needing to produce matter anew. This principle of matter conservation supports both growth and repair across all living things, allowing for sustainable development and recovery.

Question 8

A model shows a tadpole growing a longer tail. In the before panel, small molecules are shown inside the tadpole. Arrows show the molecules being assembled into larger structures in the tail region. In the after panel, the tail has more tissue. The model states: "Rearranged molecules support growth and repair."

Which statement is supported by the model about what happens to molecules during growth?

Small molecules are rearranged and built into larger structures that become new tail tissue, meaning molecules are reused as building material. (correct answer)
The tail grows because it stretches longer; the same amount of tissue is just spread out.
The tail grows because the tadpole creates new matter, so molecules inside the body do not need to change.
The tail grows because the molecules randomly bump together, so no organized building is needed.

Explanation: The core concept in middle school life science is that molecules support the growth and repair of living organisms by providing the building blocks for new tissues. Small molecules, such as those from food, are rearranged inside the body to form the complex structures needed for growth processes like lengthening a tail in a tadpole. Models demonstrate this by using arrows to illustrate how small molecule pieces are connected into longer chains and stacked layers that add tissue. To check your understanding, count the small molecules in the before panel and ensure they match the components in the larger structures of the after panel, confirming no matter is created or destroyed. A common misconception is that growth is just stretching existing tissue, but actually, it builds new structures from molecules. Conserved matter ensures that organisms can grow efficiently without needing to produce matter anew. This principle of matter conservation supports both growth and repair across all living things, allowing for sustainable development and recovery.

Question 9

A model shows a snake healing a damaged scale. In the before panel, small molecules are shown inside the snake under the damaged scale. Arrows show those molecules being assembled into larger structures that replace the damaged area. In the after panel, the scale looks complete. The model states: "Rearranged molecules support growth and repair."

Which explanation best uses evidence from the model to show that repair is more than just a change in appearance?

Because the model shows small molecules being assembled into larger structures in the damaged area, it supports that new material is built to repair the scale. (correct answer)
Because the after panel looks smoother, the scale must be repaired even if no new material was built.
Because the model has a label about repair, the molecules do not matter and are only there for memorization.
Because the snake is alive, damaged parts fix themselves without needing molecules to be rearranged.

Explanation: The core concept in middle school life science is that molecules support the growth and repair of living organisms by providing the building blocks for new tissues. Small molecules, such as those from food, are rearranged inside the body to form the complex structures needed for repair processes like healing a damaged scale in a snake. Models demonstrate this by using arrows to illustrate how small molecule pieces are connected into longer chains and stacked layers that replace damaged areas. To check your understanding, count the small molecules in the before panel and ensure they match the components in the larger structures of the after panel, confirming no matter is created or destroyed. A common misconception is that repair is just a visual change without new material, but actually, it involves building from molecules. Conserved matter ensures that organisms can repair efficiently without needing to produce matter anew. This principle of matter conservation supports both growth and repair across all living things, allowing for sustainable development and recovery.

Question 10

A student studies the model of a lizard healing a cut. In the before part, many small molecule pieces are shown inside the lizard near the cut. Arrows show the small pieces being connected into longer chains and stacked layers that fill the cut. In the after part, the cut area is covered with new tissue. The model states: "Rearranged molecules support growth and repair."

Which explanation best matches the model and shows how molecules support repair while conserving matter?

The lizard's body rearranges small molecules into larger structures that become new tissue, so the cut is repaired without creating new matter. (correct answer)
The cut heals mainly because energy turns directly into tissue, so molecules are not needed as building pieces.
The lizard repairs the cut by making new matter inside the body, so the small molecules in the model are just symbols.
The small molecules are used once and then disappear, and the tissue fills in because the body gets bigger.

Explanation: The core concept in middle school life science is that molecules support the growth and repair of living organisms by providing the building blocks for new tissues. Small molecules, such as those from food, are rearranged inside the body to form the complex structures needed for healing processes like repairing a cut in a lizard. Models demonstrate this by using arrows to illustrate how small molecule pieces are connected into longer chains and stacked layers that fill in damaged areas and create new tissue. To check your understanding, count the small molecules in the before panel and ensure they match the components in the larger structures of the after panel, confirming no matter is created or destroyed. A common misconception is that healing occurs by generating new matter from nothing, but in reality, all new tissue comes from rearranging existing molecules. Conserved matter ensures that organisms can repair themselves efficiently without needing to produce matter anew. This principle of matter conservation supports both growth and repair across all living things, allowing for sustainable development and recovery.

Question 11

A simplified model shows a tree branch healing after a small break. Before: small molecules are shown inside the branch as separate pieces near the break. During: arrows show the pieces being assembled into a larger "support layer" that bridges the break. After: the branch is strengthened at the break, showing repair. The model states: "Rearranged molecules support growth and repair."

Which prediction about growth or repair is supported by the model if the tree has less access to small molecules (for example, during a long drought)?

Repair would be slower because fewer small molecules are available to rearrange into the larger support layer needed to strengthen the branch. (correct answer)
Repair would be unaffected because repair is only a result of time passing, not building with molecules.
Repair would speed up because the branch can create the missing matter from nothing when water is limited.
Repair would still happen the same because the branch only needs to look repaired; no new structures are built.

Explanation: The core skill is predicting effects on tree branch repair when molecular access is limited, like in droughts. Small molecules in the branch are rearranged to form support layers bridging breaks. Models depict assembly with arrows creating larger structures for strengthening. Predict by considering model implications of molecule scarcity on repair speed. One misconception is that time alone heals without molecules, but building requires matter input. Conserved matter ensures trees use available atoms efficiently. This supports resilient growth and repair in plants under stress.

Question 12

A simplified model shows a fish growing. Before: small molecules are shown inside the fish as separate pieces. After: those pieces are shown connected into larger structures that make the body thicker in some areas, indicating growth. The model states: "Rearranged molecules support growth and repair."

What happens to molecules during growth, according to the model?

Small molecules are rearranged and assembled into larger structures that become part of the fish's body, so matter is conserved. (correct answer)
Molecules are used once and then vanish, so the fish must constantly replace them by creating new matter.
Growth happens without any input of molecules because the fish simply stretches bigger.
Growth happens because the fish absorbs "size" from the water, not because molecules are assembled into structures.

Explanation: The core skill is comprehending that molecules drive growth in fish by being reorganized into body-enlarging structures. Small molecules inside the fish are rearranged to connect into thicker body sections, promoting overall growth. Models represent this by transitioning from scattered pieces to connected structures in after images, highlighting the building process. Check by ensuring the model shows no disappearance or creation of molecules, maintaining conservation. A misconception is that growth occurs by stretching without adding matter, but it requires assembling new molecular structures. Conserved matter allows fish to build upon existing atoms for expansion. This supports continuous growth and repair in aquatic organisms.

Question 13

A simplified model shows a snake growing after eating. Before: small molecules are shown inside the snake as separate pieces. During: arrows show these pieces rearranged into larger structures that add a new section of body tissue. After: the snake has more body tissue (growth). The model states: "Rearranged molecules support growth and repair."

Which statement is best supported by the model as evidence for growth (not just getting bigger by stretching)?

The model shows small molecules being assembled into a new larger structure that becomes part of the snake's body tissue. (correct answer)
The snake looks longer in the after picture, so growth must be only an increase in size with no new material added.
The snake's body tissue forms because the food directly turns into body tissue without being rearranged inside the organism.
The new body tissue appears because the model shows arrows, and arrows create matter.

Explanation: The core skill is grasping how molecules contribute to snake growth by forming new body tissue sections. Small molecules from eaten food are rearranged into larger structures that extend the snake's body. Models demonstrate this with during panels showing pieces adding new tissue, evidencing true growth. Verify by noting if the model shows assembly rather than mere stretching or direct transformation. A misconception is that food turns directly into tissue without internal rearrangement, but molecules are reorganized. Conserved matter ensures all growth uses existing atoms. This principle sustains growth and repair in reptiles effectively.

Question 14

A simplified model of a growing plant stem has two panels. Before: small molecules are shown inside the stem as separate dots. After: many of those dots are shown connected into larger blocks that make up a thicker stem section, showing growth. The model states: "Rearranged molecules support growth and repair."

Which evidence from the model best supports the idea that growth happens by rearranging molecules into larger structures?

The after panel shows more connected larger blocks in the stem than the before panel, indicating small molecules were assembled into bigger structures. (correct answer)
The after panel shows the stem looks taller, which proves growth is only about size and not about building new structures.
The before panel shows dots, so the plant must be creating matter from nothing to make the stem thicker.
The model uses dots and blocks, so the plant's stem must be made of dots and blocks exactly as drawn.

Explanation: The core skill is recognizing that molecules enable growth in plants by being assembled into larger structural components. Small molecules absorbed by the plant are rearranged internally to form the complex molecules that thicken and elongate stems. Models depict this through before-and-after panels where dots connect into blocks, visually representing the building of larger structures for growth. A useful checking strategy is to compare the complexity of molecular arrangements in the model to confirm that growth involves assembly rather than just expansion. One misconception is that plants create matter from thin air, but they actually rearrange molecules from water, air, and soil. Conserved matter ensures that all new plant tissue comes from existing atoms. This principle supports sustained growth and repair in plants over time.

Question 15

A student studies the model of a lizard's tail repair. Before: the tail tip is missing and many small molecules are shown inside the lizard near the injury. After: the tail tip has regrown and the model shows those small molecules connected into larger structures that make up new tail tissue. The student concludes: "Rearranged molecules support growth and repair." Which explanation is supported by the model and conserves matter?

The tail regrows because energy alone turns into new tissue, so the small molecules are not needed.
The lizard creates brand-new matter inside its body during repair, so the larger structures appear without using the small molecules.
Small molecules inside the lizard are rearranged and joined to build larger structures, and those larger structures become new tail tissue during repair. (correct answer)
The small molecules are used once and then disappear, so they cannot be part of the new tail tissue.

Explanation: The skill tested here is understanding how molecules support growth and repair through rearrangement and assembly. Small molecules inside organisms are rearranged and joined together to build larger structures during growth and repair processes. Models show this by depicting small molecules before repair and then showing them connected into larger structures that form new tissue afterward. To check your answer, look for the explanation that shows molecules being rearranged and conserved, not created or destroyed. A common misconception is that energy alone can create new tissue or that matter appears from nowhere during repair. The correct understanding is that existing small molecules are reorganized into new structures, conserving matter while supporting growth and repair. This principle applies to all organisms, from lizards regrowing tails to plants strengthening stems.

Question 16

A model of a fish shows fin regrowth after damage. Before: the fin is torn, and small molecules are shown inside the fish near the fin. After: the fin is repaired, and the model shows the small molecules connected into larger structures in the fin. The model states: "Rearranged molecules support growth and repair." Which prediction is supported if the fish does NOT have enough small molecules available inside its body during this time?

The fin will still repair normally because growth and repair can happen without any material input.
The fin repair will be limited because fewer small molecules can be rearranged and assembled into the larger structures needed for new fin tissue. (correct answer)
The fin will repair faster because missing molecules force the body to create new matter.
The fin will repair the same because the model is meant to be taken literally as pictures, not as evidence about matter.

Explanation: This question tests understanding how availability of small molecules affects growth and repair processes. Small molecules must be rearranged and assembled into larger structures to create new tissue during repair. Models show this by depicting small molecules being connected into larger structures that form repaired tissue. To make predictions, consider what happens when fewer building blocks (small molecules) are available for assembly. A common misconception is that growth and repair can occur without material input or that organisms can create matter from nothing. The correct understanding is that limited small molecules means limited building materials for repair, restricting how much new tissue can form. This demonstrates that matter conservation applies to all growth and repair - organisms need sufficient molecular building blocks.

Question 17

A model shows a cut on a leaf being repaired. Before: a hole in the leaf and many small molecules shown inside the plant near the cut. After: the hole is covered with new leaf tissue, and the model shows small molecules assembled into larger structures in that spot. The model states: "Rearranged molecules support growth and repair." Which evidence-based explanation is best supported?

The hole disappears because matter disappears during repair, so the small molecules are no longer needed.
The new leaf tissue forms because small molecules are rearranged and joined into larger structures that become part of the repaired area, conserving matter. (correct answer)
The new leaf tissue forms because the plant grows without using molecules; growth happens automatically over time.
The new leaf tissue forms because the labels in the model cause the repair to happen, so understanding labels is the key evidence.

Explanation: The skill assessed is identifying evidence-based explanations for how molecules support growth and repair. Small molecules are rearranged and joined into larger structures that become part of the repaired leaf tissue. Models demonstrate this by showing small molecules near the damaged area that later appear assembled into larger structures forming new tissue. To find the best supported explanation, look for descriptions of molecular rearrangement that conserve matter. A common misconception is that growth happens automatically without using molecules or that understanding labels is more important than the process shown. The scientific principle is that existing molecules are reorganized into new structures during repair, conserving matter throughout. This molecular rearrangement supporting growth and repair applies to all organisms, from animals to plants.

Question 18

A model shows a puppy growing over several weeks. Before: the puppy is smaller and has many small molecules inside its body. After: the puppy has more body tissue, and the model shows small molecules connected into larger structures inside the puppy. The model includes the statement: "Rearranged molecules support growth and repair." Which evidence from the model best supports that growth is more than size and involves building new body structures from molecules?

The puppy looks bigger in the after picture, so growth must be only an increase in size.
The model shows small molecules becoming connected into larger structures inside the puppy, matching an increase in body tissue. (correct answer)
The puppy grows because it wants to get bigger, so molecules rearrange randomly.
The model labels the molecules, so memorizing the labels is the main evidence for growth.

Explanation: This question tests understanding that growth involves building new body structures from rearranged molecules, not just getting bigger. Small molecules inside organisms are rearranged and connected to form larger structures that become new body tissue. Models demonstrate this by showing small molecules before growth and then depicting them assembled into larger structures that make up increased body tissue. To identify the best evidence, look for descriptions of molecules being connected into larger structures that match tissue growth. A common misconception is that growth is only about size increase rather than building new structures from molecules. The key concept is that growth requires rearranging existing molecules into new configurations that form body tissues. This molecular rearrangement supports all types of growth in living organisms while conserving matter.

Question 19

A model shows a salamander regrowing a leg. Before: the leg is missing and small molecules are shown inside the salamander. After: the leg has regrown and the model shows small molecules assembled into larger structures in the new leg. The model states: "Rearranged molecules support growth and repair." Which claim about the molecules during regrowth is incorrect?

The small molecules are rearranged and joined into larger structures that become part of the new leg tissue.
Matter is conserved during regrowth because molecules are reorganized into new structures rather than appearing from nowhere.
The small molecules can be reused in different structures as the salamander builds new tissue during regrowth.
The salamander's leg regrows because the body pulls ready-made leg parts from food without rearranging molecules. (correct answer)

Explanation: This question tests identifying incorrect claims about molecular processes during regrowth. Small molecules are rearranged and assembled into larger structures that form new leg tissue during salamander regrowth. Models show this by depicting small molecules inside the salamander that later appear connected into larger structures forming the new leg. To find incorrect claims, look for statements suggesting ready-made parts or no molecular rearrangement. A common misconception is that organisms can pull complete body parts from food without molecular rearrangement. The correct understanding is that regrowth requires breaking down nutrients into small molecules, then rearranging these molecules into new structures. This process of molecular rearrangement supporting growth and repair while conserving matter is fundamental to all regeneration in living organisms.

Question 20

A model shows a plant stem thickening after being bent. Before: the stem is bent and has many small molecules shown inside the plant near the bend. After: the stem is stronger and has more stem tissue, and the model shows small molecules assembled into larger structures in that area. The model includes: "Rearranged molecules support growth and repair." Which explanation best matches the model?

The stem becomes stronger because the plant adds air spaces, so no molecules need to be assembled into larger structures.
The stem becomes stronger because the plant's energy turns directly into new stem tissue without rearranging molecules.
Small molecules in the plant are rearranged and joined into larger structures that become additional stem tissue, strengthening the bend area. (correct answer)
The plant grows by making new matter from nothing, so the small molecules are not connected to the new tissue.

Explanation: The skill tested is explaining how molecules support growth through rearrangement into larger structures. Small molecules inside the plant are rearranged and joined together to build larger structures that become additional stem tissue. Models show this process by depicting small molecules near the bent area that later appear assembled into larger structures forming strengthened stem tissue. To identify the best explanation, look for descriptions showing molecules being rearranged into new tissue structures. A common misconception is that energy alone creates new tissue or that matter appears from nowhere during growth. The scientific principle is that existing small molecules are reorganized into new configurations that form plant tissues, conserving matter. This molecular rearrangement process supports all types of growth and repair in living organisms.