Biology HESI A2 Practice Test

Correct Answer: A

Rationale: Tonicity refers to the movement of water across a semipermeable membrane based on the concentration of solutes. Water moves from an area of low solute concentration to high solute concentration to achieve balance. Therefore, the correct answer is A: Water. Solute (choice B) is incorrect as tonicity is not about the movement of solute particles. Cells (choice C) is incorrect as tonicity affects the movement of water, not cells themselves. "None of the above" (choice D) is incorrect as tonicity specifically involves the movement of water molecules.

Correct Answer: B

Rationale: The correct answer is B because antibiotics are designed to target and kill bacteria, not viruses like the flu. Viruses and bacteria are different types of microorganisms with distinct structures and replication mechanisms. Antibiotics work by disrupting bacterial cell processes, which viruses lack. Therefore, using antibiotics for viral infections like the flu is ineffective. Choice A is incorrect because it refers to a different type of infection, not the reason why antibiotics don't work for the flu. Choice C is incorrect because the issue lies in the antibiotic's ineffectiveness against viruses, not the dosage. Choice D is also incorrect as B clearly explains the reason why antibiotics don't work for treating the flu.

Correct Answer: B

Rationale: The correct answer is B: Smooth, skeletal, cardiac. Smooth muscle tissue is found in organs and blood vessels, skeletal muscle tissue is attached to bones for movement, and cardiac muscle tissue is found in the heart. The other choices are incorrect because they do not accurately represent the types of muscle tissue in the human body. Choice A includes organs and structures that are not muscle tissues. Choice C lists a neuron (nerve cell), epithelial (covering and lining tissue), and collagen (connective tissue), which are not types of muscle tissue. Choice D is incorrect as it does not provide the correct types of muscle tissue.

Correct Answer: A

Rationale: The correct answer is A: 18 chromosomes. During meiosis, the chromosomes are halved, resulting in gametes with half the number of chromosomes as the parent cell. Since the initial cell had 72 chromosomes, each gamete will have 36 chromosomes after the first division (meiosis I), and then after the second division (meiosis II), each gamete will have 18 chromosomes. Therefore, choice A is correct. Choices B, C, and D are incorrect as they do not reflect the halving of chromosome number during meiosis.

Correct Answer: B

Rationale: The scientist needs 12mL, which is equivalent to 0.012L. Since the bottle holds 12L, it contains more than enough solution. Therefore, choice B is correct. Choice A is incorrect because the scientist needs less than the total amount in the bottle. Choice C is incorrect because the scientist actually has more than enough. Choice D is also incorrect as the scientist does have more than required.