ATI TEAS Practice Science Test

Correct Answer: D

Rationale: The correct answer is D: Melanocyte-stimulating hormone. Melanocyte-stimulating hormone stimulates the melanocytes in the skin to produce melanin, the pigment responsible for skin color. This hormone darkens the skin by increasing melanin production. A: Follicle-stimulating hormone is involved in reproductive functions, not skin color changes. B: Growth-stimulating hormone primarily affects growth and development, not skin color. C: Thyroid-stimulating hormone regulates thyroid function, not skin color.

Correct Answer: B

Rationale: The correct answer is B: Ribcage. The ribcage is a bony structure that surrounds and protects the lungs. It consists of ribs, sternum, and thoracic vertebrae, forming a protective cage around the vital organs in the thoracic cavity. The ribs provide a barrier against external forces and help maintain the shape and integrity of the lungs. The other choices are incorrect because the femur is a bone in the leg, the scapula is a bone in the shoulder, and the skull protects the brain, not the lungs.

Correct Answer: C

Rationale: The correct answer is C: Inverse correlation. Negative variation refers to a situation where one variable increases while the other decreases, showing an inverse relationship. This is different from non-correlation (A), which implies no relationship between variables. Direct correlation (B) indicates both variables moving in the same direction, while positive correlation (D) implies both variables increasing together. Therefore, C is the only choice that accurately represents negative variation.

Correct Answer: D

Rationale: The correct answer is D because killer T cells have receptors that can recognize specific proteins displayed on the surface of infected cells. This recognition is crucial for the immune system to target and destroy infected cells effectively. The other choices are incorrect because B cells do not flag infected cells with amino acids (A), viral RNA remnants are not used for recognition by killer T cells (B), and macrophages do not directly help in identifying infected cells for killer T cell response (C). Overall, choice D stands out as the most accurate explanation based on the mechanism of T cell recognition in the immune response.

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.