Practice Test 93 - 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 river is dammed to create a reservoir. After the dam is built, a salmon population that used to migrate upstream to spawn declines sharply. Which change caused by the dam most directly explains the salmon decline?
2. Claim: Social learning (copying others) helps juveniles acquire a new foraging skill faster than learning alone. Experiment: - Juvenile birds were assigned to two conditions with the same food puzzle. - Social-learning group ($n=25$): each juvenile watched an adult solve the puzzle for 5 minutes. - Asocial group ($n=25$): juveniles had 5 minutes alone in the same room (no demonstration). Results (time to first successful solve): - Social-learning group: 19 of 25 solved within 10 minutes. - Asocial group: 6 of 25 solved within 10 minutes. Which evaluation is most accurate?
3. A fox species lives in two regions. In a cold snowy region, foxes with thick fur survive winter better than foxes with thin fur. In a hot desert region, thick fur causes overheating and lowers survival compared with thin fur. Which statement best describes the relationship between fur thickness and fitness?
4. A student eats a sugary snack. Later, their blood glucose level returns closer to normal. Which model best represents how systems integrate to regulate blood glucose at a basic level (no detailed mechanisms needed)?
5. A teacher writes two "words" using DNA's four-letter alphabet: Word 1: AAGTCC; Word 2: AACTGC. Both words are six letters long. What is the best reason these two DNA "words" could mean different things to a cell?
6. A diagram of homologous chromosomes shows one chromosome carrying alleles A–B–C and the other carrying a–b–c. After meiosis, some gametes carry A–b–C or a–B–c. Which meiotic event most directly explains these new allele combinations on the same chromosome?
7. A cell is building a polysaccharide by repeatedly joining glucose molecules. Which statement best describes what happens each time one glucose monomer is added to the growing chain?​
8. A cut on the skin starts bleeding. Platelets stick to the damaged area and release chemicals that attract and activate more platelets, causing a rapidly growing platelet plug until bleeding stops. Which type of feedback loop is this?
9. After a minor burn, the damaged area is eventually covered by new skin that functions like the original. Which outcome best shows that both cell division and differentiation occurred during healing?
10. A single bacterium divides into two daughter cells by binary fission. The two daughter cells have the same DNA as the original cell (except for rare mutations). This is an example of which type of reproduction and why?
11. A desert plant species has two root types. During drought years, 80% of plants with deep roots survive to produce seeds, while only 20% of plants with shallow roots survive. Which choice best explains why deep roots increase fitness in drought years?
12. A rabbit population has heritable variation in running speed (slow, medium, fast). In one region, a new predator that hunts by chasing rabbits becomes common. In a nearby region, this predator is absent. Which statement best describes how natural selection on speed differs between the two regions?
13. During labor, uterine contractions begin. These contractions trigger signals that make contractions stronger and more frequent, which then triggers even more strengthening until birth occurs. Which type of feedback is this?
14. Your body tends to keep its internal temperature near a target value (a set point). If you move from a cool room to a hot outdoor area, sensors detect your body temperature rising above the set point and your body responds (for example, by increasing cooling behaviors) to bring temperature back down. In this scenario, what does the term set point mean?
15. In a desert ecosystem, cactus plants make sugars using sunlight, CO2, and water. Kangaroo rats eat cactus seeds. Snakes eat kangaroo rats. Which option correctly compares producers and consumers by energy source?
16. Fossil measurements from a horse lineage show average shoulder height over time. Time (million years ago): 50, 40, 30, 20, 10, 0 (present) Average shoulder height (m): 0.45, 0.62, 0.88, 1.15, 1.38, 1.50 Which statement best describes the evolutionary trend and its magnitude?
17. A growing organism must make many new cells. Each new cell needs a membrane, enzymes, and a copy of genetic information. Which set of macromolecule syntheses best explains how these needs are met?
18. A fungal disease reduced a frog population in a pond. Biologists counted adult frogs each spring. Adult frog counts: - Year -1 (before disease): 520 - Year 0 (disease outbreak): 110 - Year 1: 160 - Year 2: 260 - Year 3: 310 - Year 6: 290 Which interpretation best matches the recovery trajectory shown by the data?
19. In a fish species, some males perform an elaborate courtship dance. Females choose dancing males more often: dancing males father more offspring per season than non-dancing males. However, dancing takes time and energy. Which statement best explains why the dance can be favored by natural selection?
20. A meadow provides 9,600 liters of drinkable water per week for a mouse population. Each mouse needs about 12 liters per week. Predators are present, but assume water is the main limiting resource for carrying capacity. What is the carrying capacity (K) for mice in this meadow?

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