Practice Test 49 - High School Biology

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

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1. In humans, a diploid cell in the ovaries or testes has 46 chromosomes (2n). During meiosis, homologous chromosome pairs separate and DNA segments can be exchanged between homologs. Which statement best explains how meiosis produces genetic diversity in gametes?
2. During cellular respiration, carbon dioxide (CO2) is produced inside cells. In humans, what typically happens to this CO2?
3. A student surveyed flower color in a patch of wildflowers. Results: - Red: 41 plants - White: 27 plants - Pink: 32 plants Which statement best describes the variation in flower color?
4. A grassland has lost many native plant species because it was converted to intensive agriculture, leaving only small patches of natural habitat. A conservation group proposes: (1) protect the remaining patches as reserves, and (2) restore native grassland corridors between patches by replacing crop fields on narrow strips of land. Which assessment best explains why combining these strategies can be more effective than using only one?
5. A herd of musk oxen is approached by wolves. The adult musk oxen move into a tight circle facing outward, while calves stand in the center. The wolves have difficulty reaching the calves and often leave without a kill. What is the best explanation for how this group behavior is cooperative?
6. A teacher draws this element flow idea on the board: CO2 (air) → glucose → macromolecules. The teacher adds: "For proteins, we also need nitrogen from soil nutrients." Which statement best matches this atom-tracking model?
7. In humans, a diploid body cell has 46 chromosomes (2n). During meiosis in the ovaries or testes, one diploid cell produces gametes used for sexual reproduction. Which statement best explains how meiosis both changes chromosome number and creates genetic diversity in gametes?
8. A city plans to increase urban biodiversity by installing nest boxes for birds and bats in parks. However, the same parks are routinely treated with broad-spectrum pesticides that reduce insect populations (a major food source). Which evaluation best identifies the main issue with the plan?
9. A lizard species shows heritable variation in skin color: some individuals are darker and some are lighter. On a dark volcanic rock habitat, darker lizards are harder for predators to see. Over many generations, the population on volcanic rock becomes mostly dark. Which statement best describes what natural selection did in this situation?
10. A lab compares DNA sequences from four species and finds the following approximate similarities to human DNA: chimpanzee 98%, mouse 85%, chicken 75%. Which conclusion best matches this molecular evidence?
11. A plant population includes two flower-color phenotypes: white and purple. A drought began between Year 3 and Year 4. Flower-color frequencies were recorded. Year 1: 60% white, 40% purple Year 2: 59% white, 41% purple Year 3: 61% white, 39% purple Year 4: 48% white, 52% purple Year 5: 33% white, 67% purple Year 6: 22% white, 78% purple Which inference is best supported by the data?
12. Two students have similar genetic potential for muscle size. One student trains with resistance exercise 4 days per week for a year; the other does not exercise. The exercising student develops noticeably larger muscles. Which idea is best supported?
13. Two people have similar genotypes that allow a wide range of possible muscle size. One person regularly strength-trains for years; the other does not exercise. The strength-trained person develops larger muscles. Which statement best explains this difference?
14. A fish population has heritable variation in body color: some fish are light and some are dark. A new predator hunts by sight in shallow water over a sandy bottom, where light fish are harder to see. After many generations in this habitat, what is the most likely result of natural selection?
15. A cycling model connects two processes: [Photosynthesis] → glucose + O₂ → [Cellular respiration] → CO₂ + H₂O Energy labels: Sunlight enters photosynthesis; ATP is produced during respiration for cell work. Which statement best matches the energy idea shown by this model?
16. A student claims: "If you reverse the overall photosynthesis equation, you get the overall cellular respiration equation." Which statement best evaluates this claim? Photosynthesis: $6CO_2 + 6H_2O + \text{light} \rightarrow C_6H_{12}O_6 + 6O_2$ Cellular respiration: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$
17. A person stands up quickly and their blood pressure briefly drops. The body responds by increasing heart rate and tightening blood vessels, raising blood pressure back toward its usual level. Which type of feedback is this?
18. Which option best describes the role of chlorophyll in the overall energy transformation of photosynthesis (without needing detailed steps)?
19. A student notes that humans have a tailbone (coccyx), which is much smaller than a tail and does not function as a tail. Some other mammals have full tails. Which type of evolutionary evidence is this, and what does it indicate?
20. A biology student examines a thin slice of the heart and notices many similar, branching muscle cells contracting together to help the heart beat. What level of biological organization is being described?

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