ati teas 7 science

Correct Answer: A

Rationale: The P wave on an ECG represents atrial depolarization. During the cardiac cycle, the electrical impulse originates in the sinoatrial (SA) node, causing the atria to contract. This depolarization of the atria is reflected as the P wave on the ECG. This occurs before the ventricles depolarize (choice B), repolarize (choice D), or before the atria repolarize (choice C). Therefore, the correct answer is A because the P wave specifically represents atrial depolarization in the cardiac cycle.

Correct Answer: B

Rationale: The correct answer is B: Insulin. Insulin is responsible for regulating blood sugar levels by facilitating the uptake of glucose into cells for energy production and storage. It helps lower blood sugar levels by promoting glucose utilization. Thyroxine (A) regulates metabolism, adrenaline (C) is involved in the fight-or-flight response, and cortisol (D) regulates stress response and metabolism, but they do not directly regulate blood sugar levels like insulin does.

Correct Answer: A

Rationale: The correct answer is A because the atomic number represents the number of protons in the nucleus of an atom, which determines the element's identity. The mass number is the total number of protons and neutrons in the nucleus, indicating the atom's mass. The number of electrons is not directly related to either the atomic or mass number, eliminating choices B and D. Choice C is incorrect because the atomic number specifically refers to the number of protons, not neutrons. Thus, choice A is the only accurate explanation of the difference between the atomic number and the mass number.

Correct Answer: B

Rationale: Ductility refers to the ability of a substance to be drawn into thin wires. This is because ductile materials can undergo plastic deformation without breaking when subjected to tensile stress. Conductivity (choice A) refers to the ability to conduct electricity, viscosity (choice C) refers to a fluid's resistance to flow, and malleability (choice D) refers to the ability of a substance to deform under compressive stress without breaking. Therefore, the correct answer is B as it specifically relates to the property of being drawn into thin wires.

Correct Answer: A

Rationale: The correct answer is A: Hydrogen gas and sodium chloride (NaCl). When NaOH reacts with HCl, a neutralization reaction occurs, forming water and a salt. NaOH + HCl -> NaCl + H2O. Sodium chloride and water are the products formed in this reaction. Hydrogen gas is also produced as a byproduct. Choices B, C, and D are incorrect as they do not represent the correct products of the reaction based on the chemical equation.