ATI TEAS 7 Science

Correct Answer: C

Rationale: The correct answer is C: RBC (Red Blood Cell). RBCs are biconcave discs that are round and flat without a nucleus. This unique shape allows for efficient gas exchange and flexibility to pass through narrow capillaries. Rationale: 1. Plasma (Choice A) is the liquid component of blood that carries various substances but does not have a specific shape or structure like RBCs. 2. Platelets (Choice B) are cell fragments involved in blood clotting and do not have the described characteristics of a biconcave disc without a nucleus. 3. WBCs (Choice D) are white blood cells responsible for immune responses and have a nucleus, unlike RBCs. In summary, RBCs are the only blood constituent among the choices that fits the description provided in the question.

Correct Answer: C

Rationale: The correct answer is C: Vitamin D. Vitamin D plays a crucial role in immune function by regulating the expression of genes involved in immune response. It helps in the production of antimicrobial peptides that defend against pathogens. Vitamin A is important for vision and skin health, not directly related to immune function. Vitamin B12 is essential for neurological function and red blood cell production. Vitamin E is an antioxidant that protects cells from damage but does not have a direct role in immune function. Therefore, the correct choice is Vitamin D as it directly supports immune system function.

Correct Answer: C

Rationale: The correct answer is C: Isotonic solution. An isotonic solution has the same concentration of solute as another solution, leading to no net movement of water across a semipermeable membrane. This term is commonly used in biology and medicine to describe solutions with equal osmotic pressure. Incorrect answers: A: Saturated solution - A saturated solution is one in which the maximum amount of solute has been dissolved at a given temperature. B: Unsaturated solution - An unsaturated solution has a lower concentration of solute compared to what it could dissolve at a given temperature. D: Concentrated solution - A concentrated solution simply means a solution with a high amount of solute dissolved in a solvent, but it does not necessarily mean it has the same concentration as another solution.

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: 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.