The correct answer is C. Proteins.
Proteins are essential for the contraction of muscles, digestion of food, and clotting of blood. They are made up of amino acids, which are the building blocks of proteins. There are 20 different types of amino acids, and the human body can only produce 11 of them. The other 9 amino acids must be obtained from food.
Proteins are found in all living things, and they play a vital role in many different processes in the body. They are essential for the growth and repair of tissues, the production of hormones and enzymes, and the transport of nutrients and oxygen. Proteins are also involved in the immune system, and they help to protect the body from disease.
The three main types of proteins are structural proteins, functional proteins, and regulatory proteins. Structural proteins provide support and structure to the body, such as collagen, which is found in skin, bones, and tendons. Functional proteins perform specific tasks in the body, such as enzymes, which help to break down food, and hormones, which regulate body functions. Regulatory proteins control the activity of other proteins, such as transcription factors, which regulate the expression of genes.
Proteins are essential for good health, and it is important to include a variety of protein-rich foods in your diet. Good sources of protein include meat, poultry, fish, eggs, dairy products, beans, nuts, and seeds.