Practice Test 90 - High School Biology

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

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1. A student compares mitosis and meiosis in humans. Which comparison is correct?
2. A lake has a sudden disease that kills most of its algae and aquatic plants. The lake also contains zooplankton that eat algae, small fish that eat zooplankton, and larger fish that eat small fish. What is the most likely long-term outcome for the consumer populations if producers remain severely reduced?
3. Commercial fishing in a coastal ocean removes most of the large predatory fish over several decades. Afterward, smaller fish and invertebrates that were once prey become much more abundant, and some seagrass beds decline due to increased grazing by certain herbivores. Which term best describes this chain of ecosystem changes?
4. A population of weeds has two alleles affecting herbicide resistance: $S$ (susceptible) and $R$ (resistant). Allele frequencies were measured before and after herbicide use increased. Year 0: $f(R)=0.04$, $f(S)=0.96$ Year 2: $f(R)=0.06$, $f(S)=0.94$ Year 4: $f(R)=0.09$, $f(S)=0.91$ Year 6: $f(R)=0.31$, $f(S)=0.69$ Year 8: $f(R)=0.58$, $f(S)=0.42$ Which statement best explains what the data show?
5. Which option correctly matches each molecule with its role in translation?
6. A plant with a particular genotype is grown in bright light and develops short, sturdy stems and dark green leaves. A genetically identical plant (same genotype) is grown in very low light and develops long, weak stems and pale leaves. What is the best interpretation?
7. Why can't the respiratory system alone supply oxygen to every cell in the body without help from the circulatory system?
8. Red blood cells are specialized for oxygen transport and typically lack a nucleus, while many white blood cells keep a nucleus and help fight infection. Both cell types come from stem cells in bone marrow and have the same DNA. What is the best conclusion about differentiation from this information?
9. DNA consists of two strands twisted into a double helix. How are the two strands arranged relative to each other?
10. A student claims: "Once a cell differentiates into a skin cell, it must have permanently removed all the genes for being a muscle cell." Which choice best evaluates this claim?
11. A fox population lives in two different regions. In Region 1, the foxes can eat rabbits, voles, insects, and berries. In Region 2, the foxes rely mostly on rabbits because few other prey are available. When a disease reduces rabbit numbers in both regions, how would biodiversity most likely affect fox population stability?
12. A student lists: (1) epithelial cell, (2) epithelial tissue lining a surface, (3) skin, (4) integumentary system. Which option orders these from smallest to largest level of organization?
13. Claim: A population of squirrels in City P evolved increased tolerance to a pollutant in the soil. Evidence to evaluate: 1) In 2005, 20% of squirrels survived in a lab soil-toxicity test; in 2025, 21% survived. 2) In 2025, squirrels from City P have higher levels of a detox enzyme after being exposed to the pollutant for 24 hours. 3) In 2025, allele $T$ (suspected to increase tolerance) is present at frequency 0.30, but there is no allele-frequency data from 2005. 4) A different city with no pollutant has 5% survival in the same lab test in 2025. Which choice best evaluates whether the evidence supports the claim that the City P squirrel population evolved increased tolerance?
14. A freshwater lake has declining native fish diversity because an invasive predatory fish was introduced and now eats juveniles of many native species. Managers propose one of the following: (1) targeted removal of the invasive fish using nets during spawning season, repeated yearly; (2) doing nothing and relying on the ecosystem to "balance out"; (3) stocking more native fish without removing the invasive predator; (4) draining the entire lake once to kill all fish. Which option is the most biologically sound strategy to preserve native biodiversity while minimizing unnecessary harm?
15. In a marine ecosystem, secondary consumers have 700 kcal of energy. Using the 10% rule, about how much energy was available to primary consumers?​
16. A fox population lives in two different habitats. Habitat X has many prey species (rabbits, voles, mice, insects, and ground-nesting birds). Habitat Y has mostly one prey species (rabbits) because other prey are rare. If rabbit numbers drop sharply one year, how does biodiversity most likely affect fox population stability?
17. A textbook diagram labels DNA as a double helix made of two long strands of nucleotides. Which statement best describes how nucleotides are organized within each strand?
18. Claim: Group living increases survival. Evidence from a controlled study: - Researchers created groups of 10 and groups of 2 in the same habitat and tracked individuals for 3 months. - Per-individual predation events: groups of 10 averaged 0.08 predation events per individual; groups of 2 averaged 0.20 per individual. - However, groups of 10 had a higher rate of parasite infection than groups of 2. Which choice best evaluates the evidence for the claim?
19. A wetland supports frogs, and the limiting resource is insect prey. The wetland produces about 2,250,000 insects per month that frogs can eat. Each frog needs about 7,500 insects per month. Estimate the carrying capacity (K) for frogs in this wetland.
20. In a lab, a leaf is kept well-watered and has access to air, but it is placed in complete darkness. According to the overall photosynthesis process, which input is missing?

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