The body is the physical structure of humans, which consists of body parts (head, neck, arms, legs, and torso) and organ systems (respiratory, circulatory, and nervous). The human body is affected by a variety of factors, including nutrition, the environment, exercise, stress, disease, and genetics. Over time, the human body ages, increasing the risk of certain age-related conditions and diseases, such as diabetes, arthritis, and heart disease. Certain supplements and foods, particularly those rich in antioxidants, can help protect the body from harmful free radicals in the environment and decrease the risk of disease.