HESI A2 Biology 2024

Correct Answer: D

Rationale: The correct answer is D: Fragmentation. Fragmentation is the form of asexual reproduction where an organism breaks into fragments, and each fragment can develop into a new individual. In this scenario, ocean waves tearing sponges into pieces allows each piece to grow into a new sponge, demonstrating fragmentation. A: Budding involves the formation of a new organism from a small outgrowth on the parent organism. This process does not involve breaking the parent organism into pieces. B: Vegetative propagation is a method of asexual reproduction in plants where new individuals are formed from vegetative parts like stems or roots. This does not apply to sponges. C: Binary fission is a form of reproduction seen in single-celled organisms where the cell divides into two identical cells. This process is not applicable to sponges, which are multicellular organisms.

Correct Answer: D

Rationale: To facilitate active transport through a membrane, ATP (adenosine triphosphate) is necessary. ATP provides the energy required for active transport processes to move molecules against their concentration gradient. Glucose (Choice A) and Sodium (Choice C) are often transported through active transport mechanisms, but they are not the energy source themselves. Oxygen (Choice B) is typically transported through passive diffusion due to its small size. Therefore, the correct answer is D (ATP) as it directly supplies the energy needed for active transport to occur.

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: B

Rationale: The correct answer is B (25%). When two heterozygous parents (Hh) with Huntington's disease reproduce, they can produce offspring with genotypes HH, Hh, or hh. The only genotype that results in the disease is HH. Therefore, 25% of the offspring are predicted to be disease-free (hh), as they would inherit the recessive allele from both parents. The other choices are incorrect because 0% is not possible since the parents are heterozygous, 50% would mean all offspring are disease-free which is not the case, and 100% would mean all offspring have the disease, which is also not true.

Correct Answer: A

Rationale: The correct answer is A because it involves testing the impact of radiation from a single cell phone on the temperature of water in a test tube in a controlled manner. By letting the phone ring for two minutes and recording the temperature before and after, the researcher can isolate the effects of radiation. Choice B introduces additional variables by varying the ringing time, making it difficult to determine the specific impact of radiation. Choice C introduces the factor of different cell phone brands, which may have varying radiation levels and could confound the results. Choice D also introduces multiple variables by using different ringing times and phone brands, making it challenging to attribute any temperature changes solely to radiation from the cell phones. Therefore, choice A is the most appropriate as it ensures a controlled experiment to directly test the hypothesis regarding the impact of cell phone radiation on water temperature.