What type of vessel carries oxygen-rich blood from the heart to other tissues of the body?

Correct Answer: D

Rationale: The correct answer is D: Arteries. Arteries are blood vessels that carry oxygen-rich blood away from the heart to supply oxygen to the tissues and organs throughout the body. Veins, choice A, carry oxygen-poor blood back to the heart, not oxygen-rich blood. Intestines, choice B, are part of the digestive system and do not play a role in carrying blood. Bronchioles, choice C, are small air passages in the lungs responsible for carrying air, not blood.

Correct Answer: D

Rationale: The correct answer is 'D: Catabolism.' Catabolism specifically involves breaking down large molecules into smaller ones to release energy. It is the opposite of anabolism, which is the process of building larger molecules from smaller ones. 'Metabolism' (choice A) is a broader term that encompasses all chemical processes in an organism, including anabolism and catabolism. 'Bioenergetics' (choice B) refers to the flow and transformation of energy in a biological system, not specifically the breakdown of molecules for energy.

Correct Answer: A

Rationale: The correct answer is A: Platelets. Platelets are small cell fragments in the blood that play a crucial role in clotting. When there is an injury, platelets adhere to the site and release chemicals that help form a clot to prevent excessive bleeding. Red blood cells transport oxygen, antigens are substances that trigger an immune response, and plasma cells are a type of white blood cell involved in producing antibodies, none of which are primarily responsible for clotting.

Correct Answer: A

Rationale: The correct answer is A. The initial event in a primary immune response is the phagocytosis of pathogens by macrophages and the subsequent presentation of their antigens, which is crucial for initiating the adaptive immune response. Neutrophils (Choice B) are also involved in the innate immune response, but they typically respond after macrophages. B lymphocytes (Choice C) produce antibodies later in the adaptive immune response, and Helper T cells (Choice D) help in coordinating the immune response but are not the first cells to act in a primary immune response.

Correct Answer: C

Rationale: Sperm maturation occurs in the epididymis, a coiled tube located on the back of each testicle. In the epididymis, sperm gain motility and the ability to fertilize an egg. It serves as a storage site for mature sperm until ejaculation. The seminal vesicles and the prostate gland contribute fluids to semen, enhancing sperm viability and motility. The vas deferens is responsible for transporting mature sperm from the epididymis to the urethra during ejaculation, but it is not where sperm maturation takes place. Therefore, the correct answer is the epididymis.