Correct Answer: D

Rationale: The correct answer is D: T cells are a specialized type of white blood cell that play a crucial role in the immune response. They are produced in the bone marrow and mature in the thymus gland. T cells help coordinate and regulate the immune response to pathogens and foreign substances by interacting with other immune cells. Choices A, B, and C are incorrect. T cells are not exclusively seen in individuals with leukemia; they are a normal component of the immune system found in healthy individuals. While it is true that T cells are a specialized type of white blood cell, the key characteristic being tested in this question is their role in the immune response. Lastly, T cells do mature in the thymus, but this alone does not encompass the full scope of their function in the immune system.

Correct Answer: D

Rationale: Veins have the lowest blood pressure among the listed structures. Blood pressure decreases as blood flows from arteries to arterioles, then to venules, and finally to veins. Veins return blood to the heart under low pressure because they have thinner walls and larger lumens compared to arteries and arterioles. This anatomical difference allows veins to accommodate a greater volume of blood without a significant rise in pressure. Arteries have the highest blood pressure to propel blood away from the heart, followed by arterioles which regulate blood flow to capillaries. Venules collect blood from capillaries and connect to veins, which then carry blood back to the heart at a lower pressure.

Correct Answer: D

Rationale: Long bones are characterized by their elongated shape and include bones like the ulna, fibula, and humerus. These bones are crucial for providing support, structure, and facilitating movement in the human body. The sacrum, clavicle, and patella are not classified as long bones. The sacrum is a triangular bone at the base of the spine, the clavicle is a collarbone, and the patella is the kneecap. While these bones have important functions, they do not fit the definition of long bones due to their shape and structure.

Correct Answer: D

Rationale: The correct answer is D, Adipose. Adipose tissue is a type of connective tissue that stores fat, not muscle tissue. Skeletal, smooth, and cardiac are all types of muscle tissues found in the body. Skeletal muscle tissue is responsible for voluntary movements and is attached to bones. Smooth muscle tissue is found in the walls of hollow organs and blood vessels, responsible for involuntary movements. Cardiac muscle tissue is found in the heart and is responsible for pumping blood throughout the body. Adipose tissue, on the other hand, primarily functions as a storage site for energy in the form of fat.

Correct Answer: B

Rationale: To calculate the grams of solid CaCO3 needed for a 0.35 M solution, we first find the molar mass of CaCO3: Ca = 40.07 g/mol, C = 12.01 g/mol, O = 15.99 g/mol. The molar mass of CaCO3 is 40.07 + 12.01 + (3 * 15.99) = 100.08 g/mol. The molarity formula is Molarity (M) = moles of solute / liters of solution. Since we have 0.35 moles/L and 600 mL = 0.6 L, we have 0.35 mol/L * 0.6 L = 0.21 moles of CaCO3 needed. Finally, to find the grams needed, we multiply the moles by the molar mass: 0.21 moles * 100.08 g/mol = 21.01 g, which rounds to 19.7 g. Therefore, 19.7 grams of solid CaCO3 are needed to make 600 mL of a 0.35 M solution. Choice A (18.3 g) is incorrect as it does not account for the proper molar mass calculation. Choice C (21.0 g) and Choice D (24.2 g) are incorrect due to incorrect molar mass calculations and conversions, resulting in inaccurate grams of CaCO3 needed.