It's believed that cardiorespiratory exercise can prevent heart disease because

How do the uv rays cause damage?   what exactly causes the skin to burn;   can you be more specific about this mechanism?   3. how do photosensitive medications increase a person's sensitivity to sunlight and therefore increase their risk of getting burned?     what kind of medications can increase photo-sensitivity, can you think of some examples?

Amino acids are important to the body because they build carbohydrates proteins complex carbohydrates simple sugars fats

How can the stress response be used in a way. for example to build resilience.