ati teas 7 science

Correct Answer: C

Rationale: The correct answer is C: Adrenal gland. The adrenal gland is located on top of the kidneys and consists of the adrenal cortex and adrenal medulla. The adrenal cortex produces hormones such as aldosterone, which helps regulate blood pressure by controlling sodium and potassium levels. It also produces cortisol, which helps regulate metabolism and immune response. The adrenal medulla produces adrenaline, which helps the body respond to stress. A: The thyroid gland is responsible for regulating metabolism and hormone production, not blood pressure or electrolyte balance. B: The pituitary gland regulates various hormones and functions but is not directly responsible for blood pressure or electrolyte balance. D: The parathyroid gland regulates calcium levels in the blood and bones, not blood pressure or electrolyte balance.

Correct Answer: C

Rationale: The myelin sheath is derived from nervous tissue, specifically glial cells. Glial cells, also known as neuroglia, support and protect nerve cells. They produce the myelin sheath, which insulates nerve fibers and allows for faster transmission of nerve impulses. Epithelial tissue (choice A) primarily covers and lines body surfaces, muscle tissue (choice B) is responsible for movement, and connective tissue (choice D) provides support and structure to the body. None of these tissues are involved in the production of the myelin sheath, making them incorrect choices.

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: D

Rationale: Step 1: Given the object is moving in a circle at a constant speed, it experiences centripetal acceleration towards the center. Step 2: According to Newton's first law, an object in motion stays in motion unless acted upon by a net force. Step 3: The only force causing the object to change its direction is the centripetal force. Step 4: Therefore, the net force acting on the object is required to continuously change its direction. Summary: Choice A is incorrect because the net force is not always present. Choice B is incorrect as centripetal force acts on the object. Choice C is incorrect as speed can be constant in circular motion.

Correct Answer: A

Rationale: The correct answer is A: Atom. An atom is the smallest unit of an element that retains its chemical properties. Atoms are composed of protons, neutrons, and electrons. Molecules (B) are made up of two or more atoms bonded together. Compounds (C) are substances composed of two or more different elements chemically bonded. Mixtures (D) are combinations of two or more substances that are physically mixed but not chemically bonded. Therefore, in this context, the correct answer is atom as it specifically refers to the smallest amount of an element that can exist independently with its unique chemical properties.