Which type of cell is primarily responsible for producing antibodies?

A. Arteries have thicker walls than veins: Arteries have thick, muscular, and elastic walls to withstand high pressure from the heart’s pumping action. This structural feature allows them to maintain blood flow and pressure throughout the circulatory system.

B. Arteries have valves inside them: Arteries generally do not have valves because blood flows under high pressure from the heart. Valves are primarily found in veins to prevent backflow.

C. Veins have thicker walls than arteries: Veins have thinner walls than arteries since they carry blood under lower pressure. Their thinner walls allow veins to expand and accommodate larger volumes of blood.

D. Veins have more elastic tissue than arteries: Arteries contain more elastic tissue to handle pulsatile blood flow. Veins have less elastic tissue and rely on valves and surrounding muscles to help return blood to the heart.

A. Cardiac muscle: Cardiac muscle is involuntary and found only in the heart. It contracts automatically to pump blood and cannot be consciously controlled, so it does not contribute to voluntary movements.

B. Smooth muscle: Smooth muscle is also involuntary and is found in the walls of internal organs such as the intestines, blood vessels, and bladder. Its contractions are automatic and not under conscious control.

C. Skeletal muscle: Skeletal muscle is under voluntary control and is attached to bones via tendons. Contraction of skeletal muscles allows deliberate movements such as walking, lifting, and writing, making it responsible for voluntary actions.

D. Striated smooth muscle: Striated smooth muscle is not a recognized type of muscle tissue. Striated muscles refer to skeletal and cardiac muscle, whereas smooth muscle is non-striated and involuntary.