The correct answer is D. Melanin.
Melanin is a pigment that gives color to skin, hair, and eyes. It is produced by cells called melanocytes. There are two types of melanin: eumelanin and pheomelanin. Eumelanin is responsible for dark hair and skin color, while pheomelanin is responsible for lighter hair and skin color. The amount of melanin produced by melanocytes is determined by genetics and environmental factors, such as sun exposure.
Luciferin is a chemical that is found in fireflies and other bioluminescent organisms. It is responsible for the production of light in these organisms. Haemoglobin is a protein that is found in red blood cells. It is responsible for carrying oxygen throughout the body. Flavonoids are a type of plant pigment that is responsible for the color of fruits and vegetables. They also have antioxidant properties.
Melanin is the most important pigment in human skin. It protects the skin from the sun’s harmful ultraviolet rays. Melanin also helps to regulate body temperature. People with darker skin have more melanin than people with lighter skin. This is why people with darker skin are less likely to get sunburned or develop skin cancer.