ATI TEAS 7 Science

Correct Answer: B

Rationale: The primary function of the small intestine is to absorb nutrients from digested food. This process involves breaking down food into smaller molecules that can be absorbed into the bloodstream for energy and growth. The small intestine has villi and microvilli that increase its surface area for efficient nutrient absorption. Choice A is incorrect because the large intestine, not the small intestine, primarily absorbs water. Choice C is incorrect as the large intestine, not the small intestine, stores waste. Choice D is incorrect because while the small intestine does produce some enzymes, its primary role is nutrient absorption.

Correct Answer: C

Rationale: The correct answer is C: Vitamin D. When the skin is exposed to sunlight, a form of cholesterol in the skin is converted into Vitamin D. This vitamin plays a crucial role in calcium absorption and bone health. Vitamin A is not synthesized in the skin but obtained through diet. Vitamin C is obtained from fruits and vegetables. Vitamin E is a fat-soluble vitamin found in nuts and seeds. In summary, only Vitamin D is synthesized in the skin upon sunlight exposure, making it the correct answer.

Correct Answer: C

Rationale: The primary function of the lymphatic system is to fight infection and remove excess fluid. Lymph nodes contain white blood cells that help fight pathogens. Lymphatic vessels collect excess fluid from tissues and transport it back to the bloodstream, aiding in immune response. Other choices are incorrect because A: Oxygen transport is primarily done by the circulatory system, B: Blood filtration is mainly carried out by the kidneys, and D: Hormone transport is primarily through the circulatory system.

Correct Answer: A

Rationale: The correct answer is A: Solid. Solids have both a definite volume and a definite shape because the particles are tightly packed and vibrate in fixed positions. This leads to a rigid structure and minimal movement, maintaining the shape and volume. In contrast, liquids (B) have a definite volume but take the shape of their container, gases (C) have neither a definite shape nor volume as they expand to fill the container, and plasmas (D) have no definite shape or volume due to their high energy state.

Correct Answer: A

Rationale: The correct answer is A: Calcitonin. Calcitonin is produced by the thyroid gland and functions to lower blood calcium levels by promoting calcium deposition in bones and inhibiting calcium reabsorption in the kidneys. This hormone opposes the action of parathyroid hormone (PTH), which increases blood calcium levels by promoting calcium release from bones and increasing calcium reabsorption in the kidneys. Thyroxine is a thyroid hormone that regulates metabolism and growth, not calcium levels. Insulin is a hormone produced by the pancreas that regulates blood sugar levels, not calcium levels. Thus, A is the correct answer as it directly regulates calcium levels in the blood through its actions on bones and kidneys.