ATI TEAS Science Test

Correct Answer: D

Rationale: The correct answer is D: Stomach. The stomach is an organ of the digestive system. Its main function is to break down and digest food, allowing the nutrients to be absorbed into the body. The stomach secretes digestive enzymes and acids to help in the digestion process. Choices A, B, and C are incorrect as the spine, lungs, and brain are not part of the digestive system. The spine is part of the skeletal system, the lungs belong to the respiratory system, and the brain is part of the nervous system.

Correct Answer: A

Rationale: The sinoatrial (SA) node is often referred to as the natural pacemaker of the heart because it is a group of cells located in the right atrium responsible for initiating the electrical signals that coordinate the heart's contractions. The SA node sets the rate and rhythm of the heartbeats, making it a crucial component in the heart's function. The other options, Submental node, Atrioventricular node, and Scalene node, are not related to the regulation of the heart's electrical activity. The Submental node is a lymph node located under the chin, the Atrioventricular node is responsible for passing electrical signals from the atria to the ventricles, and the Scalene node does not exist in the context of the heart's electrical system.

Correct Answer: D

Rationale: Enzymes are protein molecules that serve as catalysts for certain biological reactions. Enzymes are biological molecules that speed up chemical reactions in living organisms by lowering the activation energy required for the reactions to occur. They are typically proteins that have specific shapes and active sites that allow them to interact with specific substrates and facilitate reactions without being consumed themselves. The other choices are incorrect because enzymes are not irrelevant, acidic, or lipid molecules; they are primarily proteins known for their catalytic properties.

Correct Answer: A

Rationale: During a vasectomy, the vas deferens is surgically altered or cut to prevent the transport of sperm from the testicles to the urethra. This procedure is a form of permanent male sterilization. The glans penis, prostate, and urethra are not surgically altered during a vasectomy. Therefore, the correct answer is the vas deferens (Choice A), as it is the structure specifically targeted and modified in this procedure. The glans penis (Choice B) is the sensitive tip of the penis, the prostate (Choice C) is a gland vital for semen production but not involved in a vasectomy, and the urethra (Choice D) is the tube that carries urine and semen but is not surgically altered in a vasectomy.

Correct Answer: C

Rationale: In a decomposition reaction, a single reactant breaks down into two or more products. For the decomposition of ABC, a plausible set of products is A + BC. This reaction represents the breakdown of ABC into two separate components: A and BC. The correct choice C aligns with the fundamental concept of decomposition reactions, where a compound disintegrates into simpler substances. Choices A, B, and D do not reflect a proper decomposition reaction as they do not demonstrate the breakdown of the original compound into distinct components.