Practice Test 36 - High School Biology

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

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1. Many snakes have tiny internal pelvis and leg bones even though they do not have external legs. Which interpretation best describes this evidence?
2. A simple food chain is: algae → insect larvae → fish → heron. When organisms in this chain die, decomposers break them down. Which option best explains the role of decomposers in matter cycling in this ecosystem?
3. A lake was acidified by years of acid rain. After pollution controls were introduced, scientists tracked lake pH and the number of zooplankton species. Data: - Before controls (Year 0): pH 4.7; zooplankton species 6 - Year 3: pH 5.2; zooplankton species 9 - Year 7: pH 5.8; zooplankton species 13 - Year 12: pH 6.3; zooplankton species 15 - Reference lake (not acidified): pH 6.8; zooplankton species 17 Which conclusion best describes recovery completeness by Year 12?
4. A student grows genetically identical bean plants under two light conditions. In bright light, plants are shorter and dark green. In very low light, plants grow tall and pale. Which statement best describes the relationship among genotype, environment, and phenotype in this situation?
5. A DNA strand contains the bases A, T, G, and C. According to complementary base pairing rules in DNA, which bases pair together across the two strands?
6. Two ponds were sampled for water clarity (Secchi depth, m; higher = clearer) and algae abundance (chlorophyll-a, µg/L; higher = more algae). Pond X received untreated wastewater for several months (stopped at Year 0). Pond Y was undisturbed. Measurements: - Pond X pre-impact (Year -1): Secchi = 2.1; chlorophyll-a = 12 - Pond X Year 0: Secchi = 0.6; chlorophyll-a = 58 - Pond X Year 2: Secchi = 1.4; chlorophyll-a = 25 - Pond X Year 5: Secchi = 1.9; chlorophyll-a = 15 - Pond Y (all years): Secchi ≈ 2.2; chlorophyll-a ≈ 11 Which evidence best supports that Pond X is recovering by Year 5?
7. A community uses large amounts of road salt in winter. In spring, salty runoff enters a nearby freshwater pond. Which model best traces a plausible pathway to amphibian biodiversity loss?
8. Three mutations happen in the coding region of a gene: - Mutation A (substitution): ATGCCC → ATGCTC - Mutation B (insertion of 1 base): ATGCCC → ATGCCCC - Mutation C (deletion of 1 base): ATGCCC → ATGCC Which comparison is most accurate about their likely effects on the resulting protein?
9. A population of birds has a beak-size trait with three phenotypes: small, medium, and large. After a drought that leaves mostly large, hard seeds, researchers record phenotype percentages. Before drought (Year 0): small 30%, medium 50%, large 20% After drought (Year 2): small 12%, medium 41%, large 47% Which interpretation best matches the data?
10. A student runs outside on a hot day and their body temperature rises above its normal set point. In response, sweating increases and the body cools back toward normal. Which type of feedback mechanism is described?
11. In a bird species, females prefer males with brighter red feathers. In one breeding season, bright males average 3 mates, while dull males average 0.5 mates. Which statement best explains how feather brightness affects fitness?
12. A short region of a DNA template strand is: TACGAT. During transcription, RNA nucleotides base-pair to this template (RNA uses U instead of T). What mRNA sequence is produced (written 5'→3' as the complementary sequence)?
13. On a beach with very light-colored sand, biologists observed two fur-color variants of a mouse species. After one month, about 15% of light-colored mice were caught by hawks, while about 60% of dark-colored mice were caught. Which statement best connects fur color to fitness in this environment?
14. DNA stores genetic information using a four-base "alphabet" (A, T, G, C). Two DNA segments contain the same bases but in a different order: Segment 1 = ATGCCG and Segment 2 = GCATCG. Why can these two segments encode different genetic information?
15. Photosynthesis can be summarized by the equation $6CO_2 + 6H_2O +$ light energy $\rightarrow C_6H_{12}O_6 + 6O_2$. Which list shows ONLY the reactants (inputs) needed for photosynthesis?​
16. A population of frogs shows heritable variation in resistance to a fungal disease: some frogs are highly resistant and others are not. When the fungus spreads through the habitat, which frogs have higher relative fitness (reproductive success) in that environment?
17. A marine biologist measured shell length (mm) in a snail population. The smallest shell measured was 11 mm and the largest was 29 mm. What is the range of shell length in this population sample?
18. A student claims: "DNA is made of two strands, and the bases on one strand pair only with bases on the same strand." Which correction best describes how base pairing actually works in DNA?
19. A mutation occurs in a part of DNA that is not used to code for a protein (a non-coding region). Which outcome is most likely regarding the amino acid sequence of a protein?
20. Trace the movement of carbon through this sequence: atmosphere → oak tree → caterpillar → bird. Which process most directly returns carbon from the bird back to the atmosphere as CO2?

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