Biology HESI A2 2024 - Nurselytic

Correct Answer: D

Rationale: The correct answer is D, Salmonella. Salmonella bacterium reproduces via binary fission, a form of asexual reproduction where the cell divides into two daughter cells with identical genetic material. This process is common among bacteria and single-celled organisms. Mushrooms reproduce through spores, blue whales and rainbow trout reproduce sexually, involving the fusion of male and female gametes.
Therefore, choices A, B, and C are incorrect as they do not reproduce through binary fission.

Correct Answer: A

Rationale: Chlorophyll appears green to us because it primarily absorbs yellow and blue light while reflecting green light. The wavelengths of yellow and blue light are absorbed by chlorophyll for photosynthesis, which results in the green color we perceive.
Choice B is incorrect because chlorophyll absorbs yellow and blue light, not green light.
Choice C is incorrect because chlorophyll does absorb green light, but it also absorbs other wavelengths, primarily yellow and blue.
Choice D is incorrect because chlorophyll primarily absorbs yellow and blue light, not red light.

Correct Answer: C

Rationale: The correct answer is C: "Producers > secondary consumers." Producers, like plants, are the foundation of the energy pyramid, containing the highest energy content in an ecosystem. They convert solar energy into chemical energy through photosynthesis. Secondary consumers, being organisms that feed on other organisms, have lower energy content compared to producers. This hierarchy in energy content is due to the transfer of energy through trophic levels.
Choice A is incorrect because decomposers, though essential for nutrient recycling, typically have lower energy content than secondary consumers.
Choice B is incorrect because primary consumers, which feed directly on producers, have lower energy content than producers.
Choice D is incorrect because secondary consumers have lower energy content compared to primary consumers.

Correct Answer: B

Rationale: Option B is the correct approach to test the hypothesis that eating chocolate leads to acne in teenagers. This method involves having a control group (50 teenagers not consuming chocolate) and an experimental group (50 teenagers consuming two bars of chocolate daily), which allows for comparison. By having two distinct groups, researchers can assess the impact of chocolate consumption on acne development. Option A lacks a control group for comparison, making it harder to attribute any observed effects specifically to chocolate consumption. Option C only involves a single subject, which limits the generalizability of the results. Option D, where all teenagers experience both conditions, does not allow for a direct comparison between chocolate consumption and acne development, as all subjects are exposed to both conditions.

Correct Answer: C

Rationale: In a strand of DNA, adenine always pairs with thymine through two hydrogen bonds. This pairing is a fundamental aspect of DNA structure, where adenine and thymine complement each other in the double helix.
Choice A (cytosine) is incorrect because adenine does not pair with cytosine in DNA.
Choice B (uracil) is incorrect as uracil is found in RNA, not DNA.
Choice D (guanine) is incorrect as guanine pairs with cytosine, not adenine, in DNA.