Practice Test 88 - 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 single gene controls earlobe type in a class example: free earlobes (E) are dominant to attached earlobes (e). Two students with free earlobes have a child with attached earlobes. Which statement is best supported by this evidence?
2. A population of mammals already has several alleles for fur color (for example, dark and light). In one generation, many new fur-color patterns appear among offspring even though no new alleles arise that generation. What most likely explains the increase in variety of fur-color patterns?
3. A class makes an element-flow chart for a plant cell: CO2 (air) $\rightarrow$ glucose $\rightarrow$ cell membrane lipids Which statement best describes what happens to the carbon atoms along this path?
4. A thick fur coat helps mammals conserve heat in very cold climates but can cause overheating in hot climates. Which statement best describes why thick fur is considered an adaptation in the Arctic but not necessarily in a desert?
5. A bacterial population is exposed to an antibiotic. After 24 hours, 95% of bacteria with a resistance gene are still alive, but only 5% of bacteria without the gene survive. Which choice best connects the resistance trait to fitness in this environment?
6. Which list contains only substances that are produced by cellular respiration?
7. Why are food chains in most ecosystems typically limited to about 4–5 trophic levels (producers through a few consumer levels)?
8. A student compares three mutations in the coding region of a gene: Mutation A: substitution (one base replaced) Mutation B: insertion (one base added) Mutation C: deletion (one base removed) Which comparison is most accurate about their likely effects on the amino acid sequence of the protein?
9. A fossil sequence for whale evolution includes: (1) Pakicetus (land mammal with some ear features like whales), (2) Ambulocetus (semi-aquatic with limbs for walking and swimming), (3) Basilosaurus (fully aquatic with reduced hind limbs), and (4) modern whales (flippers and tail flukes). Which statement best explains how this fossil sequence supports evolution?
10. Claim: Having a sentinel (a lookout) in a group allows more time for feeding, improving foraging success. Observations over 40 hours: - When a sentinel was present, group members spent 65% of time feeding and 35% vigilant. - When no sentinel was present, group members spent 45% of time feeding and 55% vigilant. - The number of predators seen per hour was the same in both situations. Which choice best evaluates the evidence in relation to the claim?
11. Two homologous chromosomes carry different allele combinations: one has ABC and the other has abc (same genes, different alleles). During meiosis, crossing over occurs. Which outcome best describes what crossing over can produce?
12. A student claims: "Genes are not on chromosomes; chromosomes are just packaging material." Which statement best corrects this idea?
13. Two forest plots have the same species richness (same number of species), but different abundances. Plot A counts: Oak 25, Maple 25, Pine 25, Birch 25. Plot B counts: Oak 85, Maple 5, Pine 5, Birch 5. Which statement is correct?
14. A cactus population grows in a desert valley. After several dry years, fewer cacti produce flowers and many young cacti die before reaching maturity. There is plenty of sunlight and open space, but rainfall has been far below normal. What is the most likely limiting factor for the cactus population during these years?
15. A mutation occurs in a gene, but the organism's protein product is unchanged. Which is the best explanation? Assume the gene is transcribed and translated normally.
16. Why can the digestive system not, by itself, ensure that nutrients from food reach every cell in the body?
17. A student claims: "Because animals breathe out CO2, carbon only moves from organisms to the atmosphere, not the other way around." Which response best corrects the student using matter cycling?
18. A population of fish has two alleles for a protein: $A$ and $a$. Scientists measured allele frequencies over 30 generations. Generation 0: $f(A)=0.90$, $f(a)=0.10$ Generation 10: $f(A)=0.78$, $f(a)=0.22$ Generation 20: $f(A)=0.62$, $f(a)=0.38$ Generation 30: $f(A)=0.48$, $f(a)=0.52$ Which statement is most accurate?
19. A person's blood glucose is normally near $90\ \text{mg/dL}$. After eating, glucose rises to $160\ \text{mg/dL}$, but the pancreas releases little or no insulin. Over the next several hours, blood glucose stays high instead of returning near normal. Which option best identifies what is wrong with the feedback control in this scenario?
20. In a forest moth population, wing color is heritable and varies from light to dark. After many years of air pollution, tree bark becomes darker. Birds more easily spot light moths on dark bark. Over many generations, dark moths become more common. Which choice best describes the selection process that led to this adaptation?

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