Practice Test 19 - High School Biology

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

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1. Cellular respiration can be summarized as: glucose + O2 → CO2 + H2O + energy. Why is cellular respiration considered an energy-releasing (exergonic) process?
2. A fish pond is restocked each spring. Over the past 12 years, the fish population at the end of each summer has remained between 480 and 520 fish, despite occasional small fluctuations. Based on these historical data, the best estimate of the pond's carrying capacity (K) is:
3. A student is given three observations: (1) whale fossils show a land-to-water transition over time, (2) whales have small hip bones that do not attach to legs, and (3) DNA data place whales closer to hippos than to seals. Which choice best describes how these observations support evolution?
4. In snapdragons, flower color shows incomplete dominance: RR = red, WW = white, and RW = pink. Two pink plants are crossed (RW × RW). Which offspring phenotype ratio is expected?
5. A cut on the skin causes bleeding. Platelets stick to the damaged area and release chemicals that attract and activate more platelets. As more platelets arrive, even more chemicals are released, rapidly forming a clot until bleeding stops. Which type of feedback is this?
6. During labor, uterine contractions begin. These contractions trigger signals that make contractions stronger, and stronger contractions trigger even more signaling, intensifying contractions until birth occurs. Which type of feedback is described?
7. Which comparison between mitosis and meiosis is most accurate?
8. A muscle cell breaks down glucose using oxygen during cellular respiration. What are the main products (outputs) of this process?
9. A plant cell uses glucose not only to make starch and cellulose, but also as a carbon source to build other macromolecules. Which statement best describes this idea?​
10. In the overall photosynthesis process, water ($H_2O$ is a reactant). What is the most common source of this water for a land plant?
11. A student claims: "Once a cell differentiates, it usually stays that type because its pattern of gene activity is stable." Which example best supports this idea?
12. During cellular respiration, a cell breaks down glucose ($C_6H_{12}O_6$) using oxygen and produces $CO_2$ and $H_2O$. What happens to the chemical energy stored in glucose during this process?
13. A student says, "If two organisms have the same genotype, they will always have the same phenotype." Which response is the best scientific correction?
14. A population of wildflowers shows heritable variation in root depth: some plants have shallow roots, some medium, and some deep. Over several years, the region experiences frequent droughts and the soil near the surface dries out quickly. Which root-depth variant will natural selection most likely favor in this environment?
15. Claim: Without decomposers, matter would not be recycled efficiently in ecosystems. A school garden tested decomposition by placing identical leaf packs in two locations for 2 months: - Site A: leaf pack in mesh bag on forest floor (allows fungi/bacteria and small decomposers to enter) - Site B: leaf pack in a sealed plastic container with holes too small for decomposers to enter Results: 1) Leaf mass loss: Site A = 55% loss; Site B = 8% loss. 2) Soil nitrate near packs: Site A increased by 10 mg/L; Site B changed by 0 mg/L. 3) CO$_2$ measured just above packs: higher at Site A than Site B. 4) The forest floor at Site A was shaded. Which option best uses the evidence to support the claim?
16. Musk oxen can form a tight circle with calves in the center when wolves are nearby. Which benefit of group living does this behavior best demonstrate?
17. A cell has two groups of chromosomes at opposite poles. The chromosomes are starting to uncoil, and new nuclear envelopes are forming around each group. Which stage is being described?
18. In DNA, bases pair in the center of the double helix following complementary base-pairing rules. Which pairs are correct?​
19. A coastal ecosystem includes phytoplankton (photosynthetic algae), zooplankton, small fish, seabirds, and decomposers. If all producers were suddenly removed, what would most likely happen to the consumers over time?
20. A thermostat-controlled heater is set to $20\,^{\circ}\mathrm{C}$. When the room temperature drops to $18\,^{\circ}\mathrm{C}$, the heater turns on and warms the room back toward $20\,^{\circ}\mathrm{C}$, then turns off. Which type of feedback does this system model?

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