ATI TEAS Practice Science Test

Correct Answer: A

Rationale: The correct answer is A: Embryogenesis. During the first trimester of gestation, the developing organism goes through the process of embryogenesis, where the embryo forms and major organ systems begin to develop. Fertilization (B) occurs at the beginning of pregnancy, not during the first trimester. Meiosis (C) is the process of cell division that produces gametes, not directly related to the first trimester of gestation. Menstruation (D) is the shedding of the uterine lining if fertilization does not occur, not a developmental process during pregnancy.

Correct Answer: D

Rationale: The correct answer is D because a taxonomic system classifies living things based on their molecular traits, allowing for a more accurate and scientific approach to categorizing organisms. This system helps in understanding evolutionary relationships and genetic similarities among species. Choice A is incorrect as behavior is not the primary focus of taxonomy. Choice B is not the main purpose of a taxonomic system, although naming new organisms is a part of it. Choice C is incorrect as distinguishing living things from nonliving things is more related to biology in general rather than specifically to taxonomy.

Correct Answer: C

Rationale: The correct answer is C: Shaft. The shaft is the portion of the hair that is visible above the skin's surface and is not attached to the follicle. The bulb (A) is the base of the hair follicle where the hair root (B) is located and is attached to the follicle. The strand (D) refers to the entire hair structure, including the bulb, root, and shaft. Therefore, the shaft is the only part that is not physically connected to the follicle.

Correct Answer: A

Rationale: The correct answer is A: They are small and soluble. Small molecules can easily diffuse across cell membranes, while soluble molecules can dissolve in the cell's aqueous environment. This combination allows the signals to pass through the membrane and bind to intracellular receptors. Choice B (large and soluble) is incorrect because large molecules have difficulty crossing the membrane. Choices C (small and insoluble) and D (large and insoluble) are incorrect as they do not facilitate the passage of signals across the cell membrane for binding to intracellular receptors.

Correct Answer: A

Rationale: The hypodermis is primarily composed of adipose tissue, which is a type of connective tissue. Adipose tissue serves as a layer of insulation and energy storage in the body. It helps regulate body temperature and provides cushioning for organs. Adipose tissue is the main component of the hypodermis, making choice A the correct answer. Choices B, C, and D are incorrect because the hypodermis is not primarily composed of regular connective tissue, epithelial tissue, or muscle tissue.