HESI A2 Biology 2024

Correct Answer: A

Rationale: The correct answer is A: Osmosis. High-salt content foods do not require refrigeration to prevent spoilage because salt acts as a preservative by creating a hypertonic environment that draws water out of the bacteria through osmosis, causing them to dehydrate and die. This process inhibits bacterial growth and spoilage. Choices B, C, and D are incorrect because they do not explain the specific mechanism through which salt preserves food. Diffusion, active transport, and passive transport are not directly related to the preservation of high-salt content foods.

Correct Answer: C

Rationale: The correct answer is C: Lactic acid. During intense exercise, muscle cells undergo anaerobic respiration, leading to the production of lactic acid as a byproduct. This buildup of lactic acid causes muscle fatigue and soreness. Choice A, ethanol, is produced in alcoholic fermentation by yeast. Choice B, pyruvic acid, is an intermediate product in glycolysis. Choice D, oxygen, is not a byproduct of fermentation in muscle cells but is essential for aerobic respiration.

Correct Answer: B

Rationale: The correct answer is B: It is reliable, but not valid. The measurement is reliable because it consistently gives the same result (75 kg), indicating good precision. However, it is not valid because it does not accurately reflect Patient A's actual weight (68 kg). Validity refers to the accuracy of the measurement in assessing what it is supposed to measure. In this case, the scale consistently overestimates Patient A's weight, making it not valid. Choices A, C, and D are incorrect because they do not accurately reflect the situation described.

Correct Answer: D

Rationale: The correct answer is D (2 females : 1 male) because in this scenario, the male offspring will inherit the X chromosome without the hemophilia gene from the mother. The female offspring will inherit one X chromosome with the hemophilia gene from the carrier mother and one X chromosome without the gene from the father. Therefore, 2 out of 3 offspring are predicted neither to carry nor manifest the disease. Choice A (0 females : 1 male) is incorrect because females can also be carriers of hemophilia. Choice B (1 female : 1 male) is incorrect because it doesn't account for the possibility of female carriers. Choice C (1 female : 0 males) is incorrect because it doesn't consider the transmission of the X chromosome from the mother to the sons.

Correct Answer: C

Rationale: The correct answer is C: Order. Classification starts from the broadest category (Kingdom) to the most specific (Genus). Carnivora is an Order in the classification hierarchy, encompassing various families of carnivorous mammals, including dogs. Therefore, the correct classification for dogs within the Carnivora group is Order. Choices A, B, and D are incorrect because Kingdom refers to the highest taxonomic rank, Class is a level below Order, and Genus is a more specific category than Order.