(D) Kwashiorkor

Kwashiorkor is a disease caused by a deficiency of protein in the diet. It often occurs in areas where there is a lack of access to an adequate protein source. The condition is more common in developing countries and can affect children, leading to symptoms such as swelling (edema), a distended abdomen, stunted growth, and changes in skin and hair. Protein is essential for the proper growth and maintenance of tissues in the body, and a lack of it can result in severe health issues, as seen in the case of kwashiorkor. Scurvy, Beri-Beri, and Night-Blindness are caused by deficiencies of vitamin C, thiamine (vitamin B1), and vitamin A, respectively, not protein.

(C) Spinal cord

Vertebrae are part of the spinal column, also known as the backbone or spine. The spinal column is a bony structure that encases and protects the spinal cord, which is a crucial component of the central nervous system. The spinal cord is responsible for transmitting signals between the brain and the rest of the body, allowing for communication and coordination of various bodily functions.