ATI Anatomy and Physiology Online Practice

Correct Answer: D

Rationale: The correct answer is 'negative feedback mechanisms.' In biological systems, negative feedback mechanisms help maintain homeostasis by counteracting any deviations from the set point. They work to stabilize internal conditions and keep them within a narrow range. On the other hand, positive feedback mechanisms amplify changes and are not involved in maintaining stability. Choice B, 'an unstable outside environment,' is incorrect as internal stability is independent of external conditions like weather. Choice C, 'decreased atmospheric pressure,' is also incorrect as it does not directly relate to internal homeostasis.

Correct Answer: C

Rationale: Positive feedback mechanisms usually result in unstable conditions. In a positive feedback loop, the output enhances or amplifies the changes that are occurring, leading to a deviation from the initial set point. Therefore, positive feedback does not bring values back towards the set point (Choice A). Choice B is incorrect because positive feedback does not promote stability around a set point. Choice D is also incorrect as positive feedback mechanisms typically do not lead to long-term changes; instead, they intensify the initial change, causing instability.

Correct Answer: B

Rationale: Positive feedback mechanisms amplify or increase changes in a system, moving conditions away from the normal state. This makes choice B the correct answer. Choice A is incorrect as positive feedback does not cause long-term changes but rather accelerates deviations from the norm. Choice C is incorrect because positive feedback does not bring conditions back to normal; instead, it amplifies deviations. Choice D is incorrect as positive feedback does not usually lead to stable conditions but rather to further deviations from the normal state.

Correct Answer: C

Rationale: Blood cells are produced in the organs of the hematopoietic system. The correct answer is 'superior to' as this refers to the location of the organs responsible for blood cell production, typically bone marrow found in bones such as the vertebrae, ribs, and skull. 'Endocrine' (Choice A) refers to a different system responsible for hormone production. 'Skeletal' (Choice B) relates to bones but not specifically to the production of blood cells. Choices C and D, 'superior to' and 'inferior to,' do not make sense in the context of blood cell production and are incorrect.

Correct Answer: A

Rationale: The correct answer is A: Monomers. Macromolecules are built from smaller subunits called monomers. Monomers join together through chemical reactions to form larger molecules known as macromolecules. Option B is incorrect because it does not provide the accurate information regarding macromolecules. Option C is incorrect as it indicates uncertainty, which is not the case here. Option D is incorrect as there is a specific answer related to the composition of macromolecules.