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Practice Test 5 - Middle School Life Science

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

  1. A long dry period occurred between Year 5 and Year 6 in a lake region. Duck population estimates: Year 3: 1,100; Year 4: 1,150; Year 5: 1,120; Year 6: 800; Year 7: 820; Year 8: 950; Year 9: 1,020. Disturbances can change population dynamics. Which statement about the disturbance is supported by the evidence?
  2. Cells are the basis for determining whether something is living. A student observes a simplified microscope model of two samples side by side. Sample 1 (mushroom tissue) shows repeating rounded units separated by clear boundaries. Sample 2 (glass) shows a smooth, continuous area with a few cracks but no repeating rounded units. What evidence indicates that Sample 1 is living?
  3. A simplified cell model is shown; it represents interactions among parts and is not exact scale. Which statement describes an interaction supported by the model?
  4. Ecosystems provide services that support humans and other organisms. A meadow has many flowering plants. Bees and butterflies move pollen from flower to flower while feeding on nectar. As a result, more plants produce seeds, and animals that eat those seeds have more food. Which ecosystem service is shown in this meadow scenario?
  5. A class compares embryo models from four species at Stage 1 (same stage). The models show shared structures including pharyngeal arches and a tail bud. Which statement about embryological similarity is supported by the evidence in the models? (Embryological similarities can suggest relationships among species.)
  6. A lab uses CRISPR to change a gene in mosquitoes so that many offspring develop as males instead of females. In a contained population started with 100 mosquitoes, the percent of males rises from 50% to 85% over 4 generations. Humans can influence trait inheritance using technology. Which prediction about trait outcomes is supported by the scenario if the same CRISPR change continues to be passed on?
  7. Two simplified organism models are shown: - Model 1 (insect): Group labeled "Breathing" includes tubes that carry air through the body. - Model 2 (mammal): Group labeled "Breathing" includes lungs + airways. Both models include a note: "Body systems are groups of interacting parts that work together for related functions." Which statement about body systems is supported by comparing the two models?
  8. A student makes this claim about the same species of tadpoles: "Adding more food will not change population size because tadpoles will always end up at the same number." In an investigation, each tub started with 60 tadpoles and was observed for 3 weeks: - Tub 1: 1 scoop food/day → 22 tadpoles after 3 weeks - Tub 2: 2 scoops food/day → 39 tadpoles after 3 weeks - Tub 3: 4 scoops food/day → 55 tadpoles after 3 weeks Which choice is the best evaluation of the student's claim using evidence and cause-and-effect reasoning that resources can limit population size?
  9. A diagram model is shown below. It shows: (1) a food molecule entering an organism, (2) the food molecule becoming several smaller molecules inside, and (3) those smaller molecules rearranged into a different molecule labeled "new body molecule." Which statement about food breakdown is supported by the model and its evidence from before-and-after changes? Reminder: digestion breaks down and rearranges food molecules.
  10. In a forest model, a fungus decays a fallen log. Which path best traces carbon?
  11. A city park tracked populations over 6 months: caterpillars increased, songbirds decreased, and leaves on young trees decreased. Two explanations are offered: Explanation 1: "A late spring frost reduced the number of flowers and seeds, lowering food for songbirds, so songbirds decreased. With fewer birds eating caterpillars, caterpillars increased. More caterpillars ate more leaves, so leaf cover on young trees decreased." Explanation 2: "Caterpillars increased because the trees wanted to feed them. Then birds decreased because they chose to move away from caterpillars. The leaf decrease happened because leaves got tired." Which statement correctly evaluates the explanations using evidence and scientific reasoning?
  12. A student tests whether salt in water affects the growth of the same type of radish seedlings. Both groups get the same light and the same amount of water. Data (average height after 12 days): - Fresh water (0% salt): 9 cm - Salt water (2% salt): 3 cm Which environmental factor is supported by the evidence as affecting growth? (This shows that environment can affect growth.)
  13. Two breeds of rabbits differ in an inherited trait related to growth rate: Breed G (inherited to grow faster) and Breed H (inherited to grow slower). They are raised for 12 weeks in two environments: Diet 1 = high-protein feed, Diet 2 = low-protein feed. Average mass at 12 weeks is shown. Genes: Breed G vs Breed H Environment: high-protein vs low-protein diet Which prediction is supported by the evidence if both breeds are switched from Diet 2 to Diet 1 at birth?
  14. Model: Protein function → body process → trait outcome. Proteins influence traits, but a protein is not the trait itself. In a fish species, a protein helps cells sense low oxygen in water and triggers a body response that increases gill movement. A change in the protein reduces its sensing activity. Evidence collected in a lab tank: - Fish with the changed protein showed a smaller increase in gill movement when oxygen levels dropped. - Fish with the changed protein had lower survival in low-oxygen water than fish with the usual protein. Which statement about proteins and traits is supported by the model and evidence?
  15. A table shows shared anatomical features among three organisms. Which statement about common ancestry is supported by the evidence in the table? Table (1 = feature present, 0 = feature absent): - Organism X: backbone 1, four limbs 1, amniotic egg 1 - Organism Y: backbone 1, four limbs 1, amniotic egg 1 - Organism Z: backbone 1, four limbs 1, amniotic egg 0
  16. Two groups of the same kind of lizard differ in an inherited trait: Group A (inherited to grow larger) and Group B (inherited to grow smaller). They are kept for 2 months in two environments: Habitat 1 = warmer basking area, Habitat 2 = cooler basking area. Average length increase is shown. Genes: Group A vs Group B Environment: warmer vs cooler habitat Which explanation best describes the interaction between genes and environment using the evidence?
  17. Behaviors can affect reproductive outcomes. In a study of penguins during breeding season, researchers compared pairs that took turns incubating the egg with pairs where one adult incubated most of the time. They recorded egg hatching success. Data: - Turn-taking incubation: 3434 of 4040 eggs hatched - One-adult incubation: 1818 of 4040 eggs hatched What evidence links the behavior to reproductive success?
  18. Embryo images compare a frog, a chicken, and a cat at the same early stage (Stage 1). All three images highlight pharyngeal arches. A student concludes: "Since they share pharyngeal arches, frogs are the ancestors of chickens and cats." Which claim about ancestry is incorrect?
  19. Scientists compare embryos of a salamander, a turtle, and a bird at the same early stage and notice each has a tail and pharyngeal pouches. Which statement about embryological ancestry is supported?
  20. Look at the model of photosynthesis and matter movement: Model: - Arrow: air → leaf labeled carbon dioxide (matter) - Arrow: soil → roots labeled water (matter) - Arrow: Sun → leaf labeled sunlight (energy) - Inside plant: label new plant material (wood, leaves) made from sugars Which source provides matter that enters the plant and becomes part of the plant's body, based on evidence from the arrows in the model?

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