Skip to main content
Sign in Create a free account
Varsity Tutors
Sign in Sign up

Practice Test 9 - Middle School Life Science

20 questions. Answer them in any order, then submit to see your score and every explanation.

  1. A student says: "In the ecosystem model, the arrows show energy, so the model does not provide evidence about matter cycling." Which choice correctly evaluates this claim using evidence from the model? (Remember: matter cycles through ecosystems.)
  2. A chicken breeder selects only hens that lay the most eggs to be parents. After 5 generations, egg production increased, but the shells are thinner and break more often during shipping. Which prediction about future outcomes is best supported if the breeder continues selecting only for egg number and does not include shell thickness in selection?
  3. A student reads two simplified models and writes: "Reproduction type affects genetic outcomes." Model X (asexual): 1 parent yeast cell produces 2 offspring cells that match the parent's traits. Model Y (sexual): 2 parent flowering plants produce 2 offspring plants that differ in visible traits. Which claim about genetic outcomes is incorrect, based on the evidence from the models?
  4. A student is checking a classmate's conclusion using fossils from layers ordered from older to younger: Layer E (oldest) → D → C → B → A (youngest). Fossils found: - E: 2 types (Trilobite, Coral) - D: 4 types (Trilobite, Coral, Sponge, Brachiopod) - C: 4 types (Coral, Sponge, Brachiopod, Snail) - B: 2 types (Snail, Fish) - A: 3 types (Fish, Leaf, Insect) Fossil records show patterns of diversity over time. Which statement about diversity change is supported by the fossil evidence?
  5. A simplified model shows: bright flashlight interacts with an eye receptor (detection) → a signal travels toward the brain → the brain receives the signal and processes it (processing). Which claim about the brain is incorrect based on the model?
  6. A simplified model shows two parent frogs and four offspring. Parent 1 has dark skin and wide stripes. Parent 2 has light skin and thin stripes. The offspring show different combinations of skin shade (dark or light) and stripe width (wide or thin), and no two offspring in the model look exactly the same. The model states: "Sexual reproduction produces variation among offspring." Which statement about sexual reproduction is supported by the evidence in the model?
  7. A whole-organism model shows a person with a cut on the skin. The model labels the integumentary system (skin), circulatory system (blood), immune system (white blood cells), and nervous system (sensory nerves). Arrows show blood moving to the cut, white blood cells moving from blood to the cut, and nerve signals traveling to the brain. The model states: "Body systems form an integrated system." Which statement about integrated systems is supported by the model?
  8. Use the model to trace matter through multiple processes (digestion and respiration). Which path correctly traces the matter from food through digestion and then into respiration, ending with matter outputs? Model (arrows show matter movement): Food → mouth → stomach → small intestine → blood → body cells; Oxygen → lungs → blood → body cells; Outputs: carbon dioxide leaves lungs; solid waste leaves anus; liquid waste leaves bladder.
  9. In a lake, scientists tracked algae population (as a measure of algae abundance). The algae index was: Week 1 = 10, Week 2 = 12, Week 3 = 30, Week 4 = 35. Two explanations are offered: Explanation 1: Fertilizer runoff from nearby lawns increased nutrients starting in Week 3. Explanation 2: A new algae-eating snail was released in Week 3. Water testing shows nitrate levels rose sharply at Week 3. A community notice shows snails were released at Week 3 to "reduce algae." Explanations must be evaluated using evidence (fit and completeness). Which explanation is least supported by the evidence?
  10. During science class, a bright camera flash goes off. Use the pathway model Stimulus → Receptor → Brain processing → Response or stored information. Which statement about the pathway is supported by the model? (Sensory input can lead to responses or memories.)
  11. Scientists used a genetic engineering tool to insert a gene that helps rice plants resist a specific insect. They then grew seeds from the modified plants. In the next generation, 85% of the offspring plants were insect-resistant, while an unmodified comparison group stayed at about 5% resistant across generations. This is an example of humans using technology to influence trait inheritance. Which technology is being used in the resistant rice plants?
  12. A coral reef has many small spaces where fish hide from predators. The reef also reduces wave energy before it reaches the shore. This helps reef organisms survive and helps people living on nearby islands experience less wave force during normal conditions. Ecosystems provide services. Which statement about ecosystem services is supported by the reef scenario?
  13. Ecosystem model: In a meadow, bees pollinate wildflowers. A pesticide is sprayed nearby on two windy days. Afterward, flower surveys show fewer bee visits per hour and fewer new seeds forming on the flowers. Which prediction about the interaction outcome is supported by evidence and the environmental condition?
  14. A scientist studies the same species of lizard on two islands. Island R has many hawks (predators) and rocky ground. Island L has few hawks and lots of leafy plants. After marking 200 lizards of each type on each island, the scientist finds: - Island R: 70% of lizards with long legs survived 3 months; 35% of lizards with short legs survived. - Island L: 60% of lizards with short legs survived 3 months; 40% of lizards with long legs survived. Which claim about environment and traits is incorrect?
  15. Fossils provide evidence of extinction and appearance because species can be present in some rock layers and not in others. In a cliff, Layer 1 is oldest and Layer 5 is youngest. Fossils found: - Layer 1: Trilobite, Fern - Layer 2: Trilobite, Fern, Ammonite - Layer 3: Fern, Ammonite - Layer 4: Fern - Layer 5: Fern, Horse (early) Which statement about the fossil record is supported by evidence from these layers?
  16. Use the simplified cell model shown. The model labels major parts and uses arrows to show how materials move and how each part contributes to the cell working as a whole. The model also suggests that structure relates to function (for example, boundaries control what enters and leaves). Which part is responsible for controlling what goes into and out of the cell, as shown by arrows crossing the outer boundary?
  17. Photosynthesis involves inputs and outputs of matter. A student draws a model but may have made an error. Student model (arrows show matter flow; energy is shown separately): - Arrow into leaf: "oxygen (gas)" - Arrow into roots: "water (liquid)" - Arrow out of leaf: "carbon dioxide (gas)" - Arrow from leaf to plant body: "sugar (food for plant)" - Separate label: "sunlight energy" Which change would best correct the model so the matter inputs and outputs match photosynthesis?
  18. Two varieties of the same tomato plant have different inherited traits: Variety H (high-yield trait) and Variety L (low-yield trait). They are grown in two environments: Regular watering and Limited watering. Evidence after 10 weeks (average fruit mass per plant): - Regular watering: H = 1.8 kg, L = 1.2 kg - Limited watering: H = 0.9 kg, L = 0.8 kg Which prediction is supported by the evidence if both varieties are moved from limited watering to regular watering for the next growing season (with all other conditions kept the same)?​
  19. A simplified model shows heat from a hot mug (stimulus) near the hand. The model shows heat receptors in the skin with two situations: (1) the mug is near but not touching the skin; (2) the mug touches the skin. Only in situation (2) the model includes a cue "signal starts." The person then moves their hand away (response). Which prediction about detection is supported by the model? Remember: receptors detect stimuli, and detection is not the same as the response.
  20. A simplified model shows smoke odor (stimulus) moving through air in the environment into the nose and binding to smell receptors in the nasal lining. The model includes a cue "receptor activated" where the odor reaches the receptors. The person then covers their nose (response). Which statement about detection is supported by evidence in the model? Remember: receptors detect stimuli, and detection is not the same as the response.

Practice tests