Practice Test 100 - High School Biology

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

Start practice test

1. A coastal scientist monitors two reef sites after a strong storm. Reef A has many coral species, and some are known to tolerate sediment and wave damage better than others. Reef B is algae-dominated with very few coral species left. Five years later, Reef A has regained much of its coral cover, while Reef B remains mostly algae. What best explains how biodiversity affects resilience and population dynamics here?
2. A family trait is shown in this simplified description: Generation I: neither grandparent shows the trait. Generation II: neither parent shows the trait. Generation III: one child shows the trait while siblings do not. Both males and females can show the trait. Which inheritance pattern is most consistent with this evidence?
3. In a flowering plant, allele $P$ produces purple flowers and allele $p$ produces white flowers. Pollinators visit purple flowers more often, so plants with at least one $P$ allele produce more seeds. Seed production (average offspring) is: $PP$: 40 seeds, $Pp$: 40 seeds, $pp$: 10 seeds. Over time, what is the most likely outcome for allele frequencies?
4. A base substitution occurs in a gene, but it is located in a noncoding region that is not translated into protein. What is the most likely effect on the protein produced by that gene?
5. Two populations of the same insect species are exposed to a new pesticide. Scientists tracked the percent of individuals that survive exposure. Population A survival (%): Generation 0 = 10, Gen 5 = 48, Gen 10 = 78 Population B survival (%): Generation 0 = 10, Gen 5 = 18, Gen 10 = 26 Which statement best compares the rate of evolutionary change in the two populations?
6. A class builds a combined model showing multiple human activities affecting a coastal ecosystem. Which integrated pathway is most logically consistent?
7. DNA stores information using a four-letter "alphabet" (A, T, G, C). Which statement best explains how DNA can encode many different instructions using only four bases?
8. A cell is observed with condensed, X-shaped chromosomes scattered in the cell. The nuclear envelope is no longer visible, and spindle fibers are beginning to form. Which stage of mitosis is being described?​
9. A food chain begins with grass growing in sunlight. A rabbit eats the grass, and a fox eats the rabbit. Which statement best describes how the fox ultimately gets energy that originally came from the Sun?
10. The lining of the small intestine wears out quickly and must be replaced every few days. Which statement best describes how this tissue turnover happens at the cellular level?
11. A wolf pack is observed hunting elk. Two wolves run behind the elk to keep it moving, while three others spread out ahead near a narrow ravine. When the elk reaches the ravine, the wolves ahead rush in from both sides to block escape, and the pack brings the elk down. In the same area, a lone wolf usually hunts rabbits and rarely attempts elk. Which statement best explains the benefit of this cooperative behavior?
12. In an elephant herd, calves are sometimes watched and protected by multiple adults (not only the mother) while the mother feeds or travels. Compared with a solitary mother raising a calf alone, what benefit of group living does this show?
13. An energy pyramid shows these labeled amounts of energy (in kJ) available at each trophic level: - Producers: 10,000 kJ - Primary consumers: 1,000 kJ - Secondary consumers: 100 kJ Based on the diagram, which statement best describes the pattern?
14. A population of beetles lives in two nearby habitats: a dark soil field and a light sand area. Dark beetles are less visible on dark soil, while light beetles are less visible on light sand. Predatory birds hunt visually in both habitats. Which statement best predicts how beetle color relates to fitness across the two habitats?
15. In an ecosystem, producers contain 25,000 units of energy and primary consumers contain 2,500 units. How much energy is lost between producers and primary consumers?
16. A mutation changes a DNA sequence from ATGCCC to ATGCCCC (an extra C is added). This mutation occurs in the protein-coding region near the start of the gene. Which statement best describes the likely effect?
17. A wetland was drained decades ago for agriculture, reducing flood control and wildlife habitat. A restoration project proposes to plug drainage ditches, replant native wetland vegetation, and allow seasonal flooding to return. Which outcome is the best evidence that the restoration is successfully restoring ecosystem function (not just appearance)?
18. Two species of bacteria share the same genetic code system (DNA uses the same four bases, and many of the same codons specify the same amino acids). What does this molecular evidence most strongly support?
19. An animal living in a cold environment benefits from storing energy and reducing heat loss. Which synthesis-to-function connection best explains how lipids support these needs?
20. An ecosystem starts with producers containing 100,000 units of energy stored in biomass. Using the 10% rule, which set of values best estimates the energy available at each higher trophic level: primary consumers, secondary consumers, then tertiary consumers?

Practice tests