Final answer:
The biochemical reactions that contribute to aging skin include decreased collagen production, increased free radical damage, and reduced elastin synthesis.
Step-by-step explanation:
The biochemical reactions that contribute to aging skin include decreased collagen production, increased free radical damage, and reduced elastin synthesis.
1) Decreased collagen production: Collagen is a protein that provides strength and structure to the skin. As we age, the production of collagen decreases, leading to loss of elasticity and firmness in the skin.
2) Increased free radical damage: Free radicals are molecules that can cause damage to cells, including those in the skin. As we age, the body's ability to neutralize free radicals decreases, leading to increased oxidative stress and damage to the skin.
3) Reduced elastin synthesis: Elastin is another protein that helps maintain the elasticity of the skin. With age, the synthesis of elastin decreases, resulting in reduced skin elasticity and the formation of wrinkles and sagging.
Thus, the correct answer is 4) All of the above.