Correct Answer: D

Rationale: The correct answer is D: Cartilage. Cartilage is not a component of blood. Blood primarily consists of red blood cells, white blood cells, and platelets. Red blood cells are responsible for carrying oxygen, white blood cells are part of the immune system, and platelets are essential for blood clotting. Cartilage, on the other hand, is a type of connective tissue found in various parts of the body, such as the joints and nose, but it is not present in the blood. Therefore, choices A, B, and C are incorrect as they are components of blood, while choice D, Cartilage, is the correct answer as it is not a component of blood.

Correct Answer: C

Rationale: Carbohydrates are broken down into glucose during digestion, providing energy for cellular processes through glycolysis and cellular respiration. Glucose is a primary source of energy for cells, and its breakdown is essential for powering various cellular activities. Lipids are broken down into fatty acids and glycerol, not glucose. Proteins are broken down into amino acids and are not a direct source of glucose. Nucleic acids are not broken down into glucose for energy production.

Correct Answer: A

Rationale: Keratin is indeed a type of structural protein found in the skin, hair, and nails of animals. It provides strength and protection, helping to maintain the overall structure of these tissues. The other choices are incorrect as antigens are not hormonal proteins but rather are involved in immune response, channel proteins are involved in facilitating the transport of ions or molecules across cell membranes, and actin is primarily involved in cell structure and movement, not as a transport protein.

Correct Answer: D

Rationale: The correct answer is D, Myocardium. The myocardium is the cardiac muscle layer that comprises the majority of the heart's muscle mass. It is responsible for the heart's contractions, allowing it to pump blood throughout the body. The endocardium is the innermost layer of the heart lining the chambers, while the epicardium is the outermost layer covering the heart. The fibrous skeleton provides structural support and serves as an attachment point for cardiac muscle fibers. Therefore, choices A, B, and C are incorrect as they do not represent the primary muscle layer of the heart.

Correct Answer: A

Rationale: The correct answer is A, which includes Schwann cells and satellite cells as the types of glial cells found in the peripheral nervous system. Schwann cells support neurons and myelinate axons, while satellite cells provide structural support and regulate the microenvironment around neurons in the PNS. Options B, C, and D are incorrect as they refer to glial cell types that are typically found in the central nervous system, not the peripheral nervous system. Astrocytes and oligodendrocytes are primarily located in the CNS, where they perform functions such as providing structural support and forming the blood-brain barrier. Microglia are immune cells found in the CNS responsible for immune defense and maintenance of neural environment, while ependymal cells line the cerebral ventricles and the central canal of the spinal cord, contributing to the production and circulation of cerebrospinal fluid.