Practice TEAS Science Test

Correct Answer: C

Rationale: Natural Killer Cells produce Perforin to create pores in the target cell membrane, leading to target cell rupture. Perforin forms channels in the cell membrane, allowing for the entry of granzymes that induce apoptosis in the target cell. Interferon is produced by infected cells to inhibit viral replication. Apoptosis is a programmed cell death process. Antibodies are produced by B cells in response to antigens but are not involved in the direct lysis of target cells by Natural Killer Cells.

Correct Answer: A

Rationale: The correct answer is A: Skin. An organ is a group of tissues that work together to perform specific functions in the body. Skin is the body's largest organ, made up of different layers that serve various functions like protection, sensation, and regulation of body temperature. Neuron (B) is a cell type, brainstem (C) is a part of the brain, and DNA (D) is a molecule, not an organ. Skin best fits the definition of an organ, making it the correct choice.

Correct Answer: D

Rationale: Platelets play a crucial role in clotting blood. When a blood vessel is damaged, platelets rush to the site to form a plug, preventing excessive bleeding. This process, known as hemostasis, involves platelets adhering to the damaged vessel wall, releasing chemicals to attract more platelets, and forming a clot to stop bleeding. Platelets do not transport oxygen (choice A), fight infection (choice B), or produce antibodies (choice C). Thus, the correct answer is D - Clot blood.

Correct Answer: B

Rationale: The correct answer is B: Measuring wheel and mathematical formula. To measure the volume of a cube, you need to measure the length of one side using a measuring wheel and then use the formula V = s^3, where V is the volume and s is the length of one side. This method is suitable because it directly measures the side length of the cube, which is essential for calculating the volume accurately. Choice A, the triple beam balance, is used for measuring mass, not volume. Choice C, the graduated cylinder, is used to measure the volume of irregularly shaped objects using water displacement method, not ideal for a cube. Choice D, the measuring wheel alone, does not provide the formula for calculating the volume of a cube, making it less suitable compared to choice B.

Correct Answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen from the air we breathe passes into the blood vessels surrounding the alveoli, while carbon dioxide from the blood moves into the alveoli to be exhaled. The other choices are incorrect because: A: Trachea is the windpipe that carries air to and from the lungs, but gas exchange does not occur there. C: Bronchioles are small air passages that branch off the bronchi, leading air to the alveoli, but they are not the site of gas exchange. D: Diaphragm is a muscle that helps with breathing by expanding and contracting the chest cavity, but it is not directly involved in gas exchange.