TEAS Practice Test Science

Correct Answer: D

Rationale: The correct answer is D: Ventilation. Ventilation specifically refers to the mechanical act of breathing, which involves the movement of air in and out of the lungs. This process is essential for the exchange of oxygen and carbon dioxide in the body. A: Diffusion is the process of molecules moving from an area of high concentration to an area of low concentration. While diffusion plays a role in gas exchange during respiration, it is not the mechanical act of breathing itself. B: Perfusion refers to the process of blood flow through the tissues. Although perfusion is vital for delivering oxygen to the body's cells, it is not the mechanical act of breathing. C: Respiration encompasses the entire process of gas exchange in the body, including both ventilation and the exchange of gases at the cellular level. While respiration is closely related to breathing, it is not specifically the mechanical act of breathing.

Correct Answer: B

Rationale: The correct answer is B: To exchange gases. The main function of the respiratory system is to facilitate the exchange of oxygen and carbon dioxide between the body and the external environment. This process occurs in the lungs through breathing, where oxygen is taken in and carbon dioxide is expelled. Absorbing nutrients (A) is the function of the digestive system, transporting oxygen (C) is part of the circulatory system's role, and regulating blood pressure (D) is primarily controlled by the cardiovascular system.

Correct Answer: B

Rationale: The correct answer is B: Liver. The liver is responsible for filtering toxins from the blood through a process called detoxification. It metabolizes and eliminates toxins, drugs, and alcohol from the bloodstream. The kidneys (A) filter waste from the blood but do not primarily handle toxins. The heart (C) pumps blood and does not have a filtration function. The lungs (D) exchange gases and do not filter toxins from the blood. Therefore, the liver is the correct answer for filtering toxins from the blood.

Correct Answer: C

Rationale: The correct answer is C: molarity. Molarity is a concentration unit that depends on pressure because it is defined as the number of moles of solute dissolved in one liter of solution. Pressure can affect the volume of the solution, thus impacting the molarity. A: ppm (parts per million) and B: ppb (parts per billion) are mass-based concentration units and do not directly depend on pressure. D is incorrect because while molarity does depend on pressure, ppm and ppb do not.

Correct Answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen is taken in from the air and carbon dioxide is released into the air through the alveoli walls. The bronchi (A) are airways that carry air into the lungs but do not participate in gas exchange. The trachea (C) is the windpipe that connects the throat to the lungs and does not directly participate in gas exchange. The diaphragm (D) is a muscle that aids in breathing by contracting and relaxing to change the volume of the chest cavity but is not directly involved in gas exchange.