ATI TEAS Practice Test Science

Correct Answer: B

Rationale: The correct term for a microorganism that lives on or in the human body without causing harm is a commensal microorganism. Commensal microorganisms coexist with the host without causing disease or harm. Choice A, 'Bacteria,' is too broad as not all bacteria are harmless in the body. Choice C, 'Microorganism,' is a general term and does not specifically refer to the harmless nature of the organism. Choice D, 'Host,' refers to the organism harboring the microorganism, not the microorganism itself.

Correct Answer: B

Rationale: The correct answer is B: Kidneys. The kidneys play a vital role in filtering waste from the blood, regulating fluid and electrolyte balance in the body. The liver is involved in detoxification and metabolism, while the pancreas aids in digestion and blood sugar regulation. The heart is responsible for pumping blood throughout the body and does not directly filter waste from the blood.

Correct Answer: A

Rationale: The correct answer is A: Noble gases are non-reactive because they have a full valence shell with 8 electrons, making them stable and unlikely to form chemical bonds with other elements. Choice B is incorrect because Noble gases are known for their inertness and lack of reactivity. Choice C is incorrect because Noble gases have 8 valence electrons, which is a key characteristic that contributes to their stability. Choice D is incorrect because Noble gases have 8 valence electrons, not 7.

Correct Answer: A

Rationale: The correct answer is 'Ionic.' Ionic bonds are formed in salts through the transfer of electrons between atoms, leading to the attraction between positively and negatively charged ions. This results in a stable ionic compound, such as common table salt (sodium chloride). Nonpolar covalent, polar covalent, and peptide bonds are not typically found in salts. Nonpolar covalent bonds involve the equal sharing of electrons, polar covalent bonds involve unequal sharing of electrons, and peptide bonds are specific to proteins, not salts.

Correct Answer: D

Rationale: The correct answer is Polymerase. Polymerase is the enzyme responsible for adding nucleotides to a growing DNA chain during DNA replication. Helicase unwinds the DNA double helix to separate the DNA strands for replication, Ligase joins DNA fragments together by catalyzing the formation of phosphodiester bonds between them, and Nuclease cuts or degrades DNA strands. Therefore, choices A, B, and C are incorrect in the context of adding nucleotides to a growing DNA chain.