ATI TEAS Science Questions

Correct Answer: A

Rationale: The correct answer is A: Pulmonary semilunar valve. The pulmonary semilunar valve is located between the right ventricle and the pulmonary artery. It opens to allow blood to be pumped into the pulmonary artery but closes to prevent blood from returning back into the right ventricle. The aortic semilunar valve is located between the left ventricle and the aorta. The tricuspid valve is located between the right atrium and right ventricle, and the mitral valve is located between the left atrium and left ventricle. Therefore, the pulmonary semilunar valve is the specific valve responsible for preventing the backflow of blood into the right ventricle during the cardiac cycle.

Correct Answer: A

Rationale: AIDS targets and destroys Helper T-Cells, which play a crucial role in coordinating the immune response. By affecting these cells, AIDS prevents the activation of other important immune cells like Cytotoxic T-Cells or B-Cells. This disruption in the immune system's communication and response mechanisms leads to immune system failure and increased vulnerability to infections. Choices B and C are incorrect because they refer to the role of IgE in allergic reactions, which is not directly related to how AIDS impairs the immune system. Choice D is also incorrect as Helper T-Cells being destroyed in AIDS is not about deceiving the body into attacking itself, but rather the direct impact on immune system function.

Correct Answer: C

Rationale: The correct answer is C, 'The vagina.' The muscular tube that connects the outer surface to the cervix in a woman's birth canal is called the vagina. The vagina serves as the passageway for menstrual flow, sexual intercourse, and childbirth. The cervix, not the uterus, connects the vagina to the uterus. The ovaries, on the other hand, are the organs responsible for producing eggs and female hormones, but they are not the muscular tube connecting the outer surface to the cervix in the birth canal.

Correct Answer: B

Rationale: The correct answer is B: 'Indefinite shape and definite volume.' A gas does not have a definite shape as it takes the shape of its container, conforming to its surroundings. However, a gas does have a definite volume because it fills the entire volume of the container it occupies. This characteristic allows gases to expand to fill the available space provided by the container, while their volume remains constant within that container. Choice A is incorrect because gases do not have an indefinite volume but rather a definite volume. Choice C is incorrect as gases do not have a definite shape but take the shape of their container. Choice D is incorrect as gases do not have a definite shape and their volume is definite, not indefinite.

Correct Answer: C

Rationale: The correct answer is C: Monosaccharide. Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar unit. They are considered the carbohydrate monomers from which larger carbohydrates like disaccharides (composed of two sugar units) and polysaccharides (containing multiple sugar units) are built. Choices A and B, Disaccharide and Lactose, are not monomers but rather specific types of carbohydrates made up of multiple sugar units. Choice D, Thymine, is a nitrogenous base present in DNA and RNA, not a carbohydrate monomer.