HESI A2 Biology Practice Test

Correct Answer: D

Rationale: The correct answer is D because all the choices - the pituitary gland, the thyroid gland, and the adrenal glands - are indeed components of the endocrine system. Each of these glands secretes hormones directly into the bloodstream to regulate various bodily functions. The pituitary gland controls other endocrine glands, the thyroid gland regulates metabolism, and the adrenal glands manage stress responses. Therefore, all of these glands play vital roles in the endocrine system. The other choices (A, B, C) are incorrect because they are all components of the endocrine system.

Correct Answer: A

Rationale: Epithelial cells are correct to be classified as polarized because they have distinct apical and basal surfaces. The apical surface faces the external environment or a body cavity, while the basal surface is anchored to the underlying connective tissue. This polarity is essential for the specialized functions of epithelial cells, such as absorption, secretion, and transportation. Therefore, choice A is the correct answer. Choices B and C are incorrect because epithelial cells are not neutral and are not necessarily larger than other cells. Choice D is incorrect because epithelial cells do have unique characteristics that differentiate them from other cell types.

Correct Answer: A

Rationale: The correct answer is A: Adenine. Adenine is a nucleotide base that consists of two fused carbon rings, making it a purine base. The two rings in adenine are essential for its structure, function, and hydrogen bonding with thymine in DNA. The other choices, B, C, and D, are all pyrimidine bases, which have only one carbon ring. Therefore, adenine is the only base among the options that has two carbon rings, making it the correct answer.

Correct Answer: B

Rationale: To focus an image using a compound microscope, adjusting the fine adjustment is correct as it allows for precise focusing when switching magnifications. Coarse adjustment is only used initially to bring the specimen into view, while the stage adjustment is used to center the specimen. Therefore, B is correct as it ensures clear and sharp image focus without unnecessary readjustments. Choices A and C are incorrect as they do not address the specific need for precise focusing when changing magnifications, leading to potential blurriness or loss of focus in the image.

Correct Answer: D

Rationale: The correct answer is D because all the choices - the pituitary gland, the thyroid gland, and the adrenal glands - are indeed components of the endocrine system. Each of these glands secretes hormones directly into the bloodstream to regulate various bodily functions. The pituitary gland controls other endocrine glands, the thyroid gland regulates metabolism, and the adrenal glands manage stress responses. Therefore, all of these glands play vital roles in the endocrine system. The other choices (A, B, C) are incorrect because they are all components of the endocrine system.