TEAS 7 Science Practice Test

Correct Answer: A

Rationale: The correct answer is A: capillaries. Capillaries are tiny blood vessels where the exchange of oxygen and nutrients occurs between the blood and tissues through diffusion. Capillaries have thin walls to facilitate the exchange process efficiently. Veins carry blood back to the heart, ventricles are chambers of the heart, and arteries carry blood away from the heart. Thus, they are not sites for oxygen exchange between blood and tissues.

Correct Answer: A

Rationale: Correct Answer: A - A strong acid completely ionizes in water. Rationale: 1. Strong acids fully dissociate into ions in water, leading to a high concentration of H+ ions. 2. This complete ionization results in a low pH. 3. Strong acids do not reversibly donate more than one proton or contain metal atoms. 4. Strong acids can decompose under certain conditions, so choice D is incorrect.

Correct Answer: B

Rationale: The correct answer is B: sinoatrial node. The sinoatrial node is a cluster of specialized cells in the right atrium responsible for initiating the electrical impulses that regulate the heartbeat. It acts as the heart's natural pacemaker by setting the pace for the heart's contractions. The other choices are incorrect because: A: Sinus venosus is an embryonic structure in the heart, not the natural pacemaker. C: Atrioventricular node is responsible for conducting the electrical signal from the atria to the ventricles, not for generating the initial signal. D: Tricuspid valve is a heart valve that prevents backflow of blood from the right ventricle to the right atrium, not involved in generating electrical signals.

Correct Answer: B

Rationale: The correct answer is B: make observations. This is the initial step of the scientific method because it involves gathering information about a phenomenon or problem. Observations help in identifying patterns, trends, and potential areas for investigation. Forming a hypothesis (A) comes after making observations, as it is a proposed explanation based on those observations. Analyzing data (C) and forming a question (D) also follow after making observations. Making observations is crucial as it sets the foundation for the rest of the scientific method process.

Correct Answer: C

Rationale: The correct answer is C: synapse. Neurotransmitters are chemicals that transmit signals between neurons. The synapse is the gap between neurons where these chemical messages are transmitted. Schwann cells are responsible for myelinating axons, ganglion is a cluster of nerve cell bodies, and the axon is the part of a neuron that carries the signal away from the cell body. Therefore, the synapse is the structure specifically involved in transmitting neurotransmitters between neurons.