Practice Test 83 - High School Biology

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

Start practice test

1. A city plants street trees in two ways. Plan A uses a single tree species along most streets. Plan B uses many tree species. A pest arrives that kills only one tree species. How does biodiversity most likely affect the stability of the city's street-tree population over time?
2. A plant population includes individuals with either hairy leaves or smooth leaves. A drought began at Year 4. Trait frequencies were recorded: Year 0: 48% hairy, 52% smooth Year 2: 49% hairy, 51% smooth Year 4: 50% hairy, 50% smooth Year 6: 63% hairy, 37% smooth Year 8: 74% hairy, 26% smooth Which interpretation best fits the pattern?
3. A cactus species lives in a desert where water is scarce. In the ancestral population, plants varied in leaf size due to heritable differences. Plants with smaller leaves lost less water and produced more seeds than plants with larger leaves. Over many generations, the population evolved spines instead of broad leaves. Which explanation best connects this change to natural selection?
4. A plant leaf cell contains both chloroplasts and mitochondria. Which statement correctly describes what the plant can do compared with an animal cell? (Use the overall equations as a guide.) Photosynthesis: $6CO_2 + 6H_2O + \text{light} \rightarrow C_6H_{12}O_6 + 6O_2$ Respiration: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$
5. A population of bacteria was sampled in a hospital each year to measure the percent of cells resistant to Antibiotic X. Year: 2005, 2010, 2015, 2020, 2025 Resistance (%): 3, 12, 35, 68, 86 Which statement best interprets the evolutionary trend shown by these data?
6. A rabbit population includes individuals that run fast and individuals that run more slowly (a heritable difference). In one area, foxes frequently hunt rabbits. In a nearby fenced area, foxes are absent. Which outcome best matches how natural selection depends on the environment?
7. A muscle cell uses ATP to power contraction (ATP 9 ADP + P + energy). Where does the energy to rebuild ATP from ADP mainly come from during cellular respiration?
8. A bird population has two beak types: thick (T) and thin (t). Thick-beaked birds produce an average of 4 offspring that survive to adulthood, while thin-beaked birds produce an average of 2 such offspring. If these differences continue, what will happen to the frequency of the thick-beak trait over generations?
9. Which statement best explains why glucose ($\mathrm{C_6H_{12}O_6}$) is considered an energy-storage molecule after photosynthesis?
10. Two ecosystems follow the 10% rule. - Ecosystem A: Producers = 20,000 units - Ecosystem B: Producers = 200,000 units How much energy is available to secondary consumers in Ecosystem B?
11. Two forests experience the same insect outbreak that attacks only one tree species. Forest A has about 30 tree species. Forest B is a plantation with mostly one tree species and only a few other species. Which outcome best matches how biodiversity influences population stability and overall forest function?
12. Suppose all producers (plants and algae) were suddenly removed from an ecosystem, but all consumers and decomposers remained. What would most likely happen over time?
13. A human body cell contains about $2$ meters of DNA in total, but the nucleus is only about $10\ \mu m$ across. Which choice best explains how this long DNA fits inside the nucleus and what a chromosome is?
14. A class is building a closed bottle ecosystem with aquatic plants and small animals. The bottle is sealed to matter (no CO2/O2 exchange with the room) but placed under a lamp. Which statement best matches a correct model of matter cycling and energy flow in the bottle?
15. Photosynthesis can be summarized as: carbon dioxide + water + light energy $\rightarrow$ glucose + oxygen. What are the products (outputs) of photosynthesis?
16. A student is asked to label arrows in a diagram connecting photosynthesis and cellular respiration. The diagram has two boxes: "Photosynthesis" and "Cellular respiration." Four unlabeled arrows connect the boxes (two arrows from photosynthesis to respiration, and two arrows from respiration to photosynthesis). Which labeling correctly represents matter cycling between the processes?
17. In a species of fish, scale pattern shows codominance: allele S produces striped scales, allele D produces dotted scales, and heterozygotes (SD) show both stripes and dots on the same fish. Two SD fish are crossed (SD × SD). Which phenotype ratio is expected in the offspring?
18. Which statement best describes the relationship among DNA, genes, and chromosomes in a human cell?
19. A plant cell has many glucose (C6H12O6) molecules available after photosynthesis. The cell builds starch by linking glucose monomers into a long chain. Which statement best describes what happens during this synthesis process?
20. A plant is making nucleic acids (DNA/RNA). Glucose provides many of the carbon-containing building blocks, but the plant also needs phosphorus (P). Where do the phosphorus atoms in nucleic acids come from, and what happens to them during synthesis?

Practice tests