ATI TEAS Science Questions

Correct Answer: A

Rationale: Totipotent stem cells have the unique ability to differentiate into any cell type in the human body and can generate a complete organism. They are considered the most versatile type of stem cells, capable of developing into all cell types, including extraembryonic tissues. Choice A, Totipotent stem cells, is the correct answer as it specifically describes stem cells with the broadest differentiation potential. Choice B, Multipotent stem cells, refers to stem cells that can differentiate into a limited range of cell types. Choice C, Pluripotent stem cells, can give rise to almost all cell types, but not the complete organism like totipotent stem cells. Choice D, Hematopoietic stem cells, are a type of multipotent stem cells that give rise to various blood cell types, but do not have the same broad differentiation potential as totipotent stem cells.

Correct Answer: B

Rationale: Correct. Positive feedback loops enhance or amplify changes, which can sometimes be harmful as they drive processes further from equilibrium. In contrast, negative feedback loops work to counteract deviations from a set point, promoting stability. Choice A, 'Negative feedback loop,' is incorrect because negative feedback loops inhibit or reduce changes, promoting stability. Choice C, 'Inhibitory feedback loop,' is incorrect as it is synonymous with negative feedback loops. Choice D, 'Stimulating feedback loop,' is incorrect as it inaccurately describes the nature of positive feedback loops.

Correct Answer: C

Rationale: The corrected answer is C. Elastic arteries, like the aorta, are the largest arteries in the body. They possess elastic fibers in their walls, allowing them to stretch and recoil in response to the pulsatile nature of blood flow from the heart. This elasticity helps to maintain blood pressure by absorbing the pressure waves generated by the heart's contractions and ensuring continuous blood flow to the organs. Choices A, B, and D are incorrect because elastic arteries are not the smallest arteries, do not constrict and dilate frequently, are not medium-sized arteries for distributing blood to various organs, and are not thin-walled arteries supplying blood to capillaries. Elastic arteries have a specific structure and function related to their ability to accommodate blood pressure changes due to their elastic properties, which is essential for the cardiovascular system's proper functioning.

Correct Answer: B

Rationale: The correct answer is B, Skeletal muscle. Skeletal muscle is both voluntary and striated, as well as attached to bones, allowing for movement. Smooth muscle, on the other hand, is involuntary and typically found in the walls of internal organs, controlling functions like digestion. Cardiac muscle is also striated, but it is involuntary and specifically found in the heart, responsible for cardiac contractions to pump blood. 'Epithelial muscle' is an incorrect term; epithelial tissue is a type of tissue that forms the linings of various body surfaces and structures, not a muscle type.

Correct Answer: C

Rationale: The correct answer is an increase in CO2. In a healthy individual, the primary drive to breathe is regulated by the levels of carbon dioxide (CO2) in the blood. When CO2 levels increase, it triggers the body to increase the rate and depth of breathing to eliminate excess CO2 and restore the balance. This response is more powerful than other stimuli such as acidosis, alkalosis, or loss of oxygen. While acidosis and alkalosis can affect breathing, an increase in CO2 has a more direct and immediate impact. Loss of oxygen (hypoxia) is a potent stimulus, but the body's response to increased CO2 levels is generally more pronounced and immediate in healthy individuals.