HESI A2 Biology Practice Test

Correct Answer: D

Rationale: Step-by-step rationale: 1. Diploid organisms can be multicellular or unicellular, so A is not universally true. 2. Diploid cells can be somatic or germ cells, so B is not always true. 3. Diploid cells always have two sets of homologous chromosomes, making C true. 4. Since C is true and A and B are not always true, the correct answer is D.

Correct Answer: D

Rationale: The correct answer is D because it follows the structure of a hypothesis: it states a relationship between two variables (exposure to red light and plant growth) that can be tested. It is specific, testable, and predicts an outcome. Choice A is a general statement, not a testable hypothesis. Choice B is subjective and not testable. Choice C lacks specificity and does not clearly define the relationship being tested.

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: B

Rationale: The correct answer is B: Create energy. Mitochondria are known as the powerhouse of the cell because they produce ATP, the primary energy source for cellular functions. They do this through a process called cellular respiration. Option A is incorrect as the nucleus controls the cell. Option C is incorrect as protein synthesis occurs in the ribosomes. Option D is incorrect as waste packaging is typically done by lysosomes.

Correct Answer: A

Rationale: The correct answer is A: The nucleus. DNA is stored in the nucleus of a cell because it contains the genetic material that carries instructions for the cell's functions. The nucleus is specifically designed to protect and regulate access to the DNA. Ribosomes (B) are responsible for protein synthesis, not DNA storage. Endoplasmic reticulum (C) is involved in protein and lipid synthesis, but not DNA storage. Mitochondria (D) have their own DNA, but the majority of the cell's DNA is stored in the nucleus.