Biology

The correct answer is: C.Structural support

Proteins have a wide variety of functions in living organisms, but structural support is one of their primary roles. Proteins make up many of the building blocks of cells, tissues, and organs. Examples include collagen (in connective tissues), keratin (in hair and nails), and actin and myosin (in muscles).

Here’s a quick explanation of the other options:

A.Source of energy: Proteins can be broken down for energy when necessary, but they are not the body's primary source of energy. Carbohydrates and fats are m...