ati teas 7 science

Correct Answer: B

Rationale: The correct answer is B: Atom. An atom is the smallest unit of matter that retains the properties of an element. Atoms are made up of protons, neutrons, and electrons. A molecule (A) consists of two or more atoms bonded together. A compound (C) is a substance composed of two or more different elements chemically bonded. An element (D) is a pure substance made up of only one type of atom. Therefore, the smallest unit of matter is the atom.

Correct Answer: C

Rationale: The correct answer is C: Exceptional stability of the nucleus. Magic numbers are specific numbers of protons or neutrons that result in a more stable nucleus due to the arrangement of nucleons in energy levels. This stability is a result of closed shells, leading to lower energy states and less tendency for decay. Choices A and B are incorrect as magic numbers actually contribute to increased stability, leading to decreased nuclear instability and lower radioactive decay rates. Choice D is incorrect because magic numbers do not lead to increased instability or enhanced decay rates, but rather to exceptional stability.

Correct Answer: A

Rationale: The correct answer is A: Hypothalamus. The hypothalamus plays a vital role in regulating body temperature by responding to internal and external temperature changes. It coordinates the body's response to maintain a stable temperature through processes like sweating or shivering. B: Cerebellum is responsible for coordinating movement and balance, not body temperature regulation. C: Pituitary gland regulates hormone production but not directly involved in body temperature regulation. D: Thyroid gland controls metabolism and energy levels but not primarily responsible for regulating body temperature.

Correct Answer: A

Rationale: The correct answer is A: Perpendicular to the direction of wave travel. In a transverse wave, particles of the medium move up and down (or side to side) perpendicular to the direction of wave travel. This motion creates crests and troughs in the wave. This motion is what characterizes a transverse wave, where the disturbance is perpendicular to the direction of energy transfer. Choices B, C, and D are incorrect because in a transverse wave, the particles do not move parallel to the direction of wave travel (B), in a circular motion (C), or opposite to the direction of wave travel (D).

Correct Answer: B

Rationale: The correct answer is B: To secrete digestive enzymes. The pancreas secretes enzymes such as amylase, lipase, and proteases that help break down carbohydrates, fats, and proteins in the small intestine. This aids in the digestion and absorption of nutrients. Storing bile (A) is the role of the gallbladder, digesting proteins (C) is primarily done by the stomach and small intestine, and absorbing nutrients (D) mainly occurs in the small intestine.