Practice Test 99 - 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 general negative feedback loop in homeostasis can be summarized as: deviation from set point → detection → response → condition moves back toward set point. Which choice best matches this idea using body temperature as an example?
2. In a meadow ecosystem, sunlight shines on grass. A simplified food chain is: Grass → Rabbit → Fox, and after organisms die, fungi and bacteria break down the remains. Which statement best explains why producers are essential in this ecosystem?
3. Consider the overall equations: Photosynthesis: $6CO_2 + 6H_2O + \text{light} \rightarrow C_6H_{12}O_6 + 6O_2$ Cellular respiration: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$ Which choice correctly describes the energy transformation in each process?
4. A population of rabbits has two fur-length phenotypes: short and long. The phenotype frequencies are recorded over time. Generation 0: 48% short, 52% long Generation 10: 49% short, 51% long Generation 20: 50% short, 50% long Generation 30: 49% short, 51% long Which conclusion is most reasonable based on these data?
5. A farmer tracks the number of weeds in a field that survive a particular herbicide. Each year, 200 weeds are tested. Year 1: 6 survivors (3%) Year 2: 18 survivors (9%) Year 3: 44 survivors (22%) Year 4: 96 survivors (48%) Year 5: 140 survivors (70%) Which statement best explains what these data suggest?
6. A lake has declining native fish and fewer aquatic insects. Testing shows high nutrient runoff from nearby farms causes frequent algal blooms that reduce oxygen levels. Managers propose adding more fish to the lake each year (stocking) to boost fish numbers. Which critique best explains why stocking alone may be a weak biodiversity-preservation strategy here?
7. Claim: Decomposers recycle matter by releasing nutrients from dead organisms back into the soil for plants to reuse. A student set up two pots with the same mass of dead leaf litter added: - Pot A: normal garden soil (contains decomposers) - Pot B: sterilized soil (heated to kill decomposers) Results after 4 weeks: 1) Pot A: leaf litter mass decreased; soil nitrate increased. 2) Pot B: leaf litter mass changed very little; soil nitrate stayed low. 3) Both pots received the same amount of sunlight and water. 4) The leaves added were brown and dry. Which set of evidence is most relevant and sufficient to support the claim?
8. A plant uses glucose (C6H12O6) to build a lipid (fat) molecule that has a much higher ratio of hydrogen to oxygen than glucose. Which statement best explains this change while still following conservation of matter?
9. Which statement best summarizes conservation of matter during the synthesis of macromolecules in a plant?
10. A bee colony relies on worker bees to communicate the location of rich flower patches to other members of the hive. Compared with a solitary bee, what is the key advantage of living in a colony here?
11. On an island, average beak depth (mm) in a finch population was measured after different rainfall conditions. Year: 1976, 1978, 1980, 1983, 1985, 1987 Rainfall condition: Wet, Drought, Wet, Drought, Wet, Drought Mean beak depth (mm): 8.1, 9.0, 8.3, 9.2, 8.4, 9.3 Which interpretation best matches the pattern and its relationship to the environment?
12. Two systems are described below: System 1: Continuously measures an internal condition, compares it to a set point, and adjusts its response based on the new measurement. System 2: Produces a fixed response whenever the environment changes, without checking whether the internal condition has returned to the set point. Which statement is most accurate?​
13. Claim: Group living increases survival. Evidence reported by a student: - The student watched one group of animals for 2 days and saw that none were eaten by predators. - The student also saw one solitary animal get attacked once. Which choice best evaluates the strength of this evidence?
14. A student claims: "Packaging DNA into chromosomes changes the DNA sequence to make it shorter." Which statement is the best correction?
15. A rabbit population lives in a snowy region. Fur color is heritable and varies: some rabbits are white, others are brown. A series of years with little snowfall leaves the ground mostly brown. Foxes hunt by sight. Over multiple generations, the rabbit population becomes mostly brown. Which explanation best matches natural selection?
16. A lab compares two human cells. Cell 1 is a cardiac muscle cell that contracts repeatedly. Cell 2 is a neuron that sends signals using long extensions. Both cells contain the same DNA. Which statement best explains why they produce different proteins?
17. A plant population has three flower-color phenotypes: red, pink, and white. The percentages of each phenotype were recorded over 5 generations. Generation 1: Red 40%, Pink 40%, White 20% Generation 2: Red 41%, Pink 39%, White 20% Generation 3: Red 39%, Pink 41%, White 20% Generation 4: Red 40%, Pink 40%, White 20% Generation 5: Red 40%, Pink 40%, White 20% Which conclusion is best supported by the data?
18. In a condensation (dehydration synthesis) reaction, two glucose monomers join to form a disaccharide, and the reaction can repeat to build a polysaccharide. What happens to water during each joining step?
19. A lake receives a pulse of pollution from a factory spill. Oxygen levels drop and some fish die. After cleanup, oxygen levels and fish populations gradually return to near pre-spill levels over the next few years. Which statement best describes what this example shows?
20. A plant population has two flower-color phenotypes: white and purple. Purple-flowered plants produce, on average, twice as many seeds as white-flowered plants in the same environment. If this difference stays consistent for many generations, what is the most likely outcome for the trait frequencies?

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