Proteins are vital in which of the following processes in the body?

Proteins play a crucial role in building new cells and repairing tissues, making them essential for growth, maintenance, and recovery in the body. They are composed of amino acids, which serve as the building blocks for various bodily structures, including muscles, skin, organs, and the immune system. This function is vital not only during childhood and adolescence, when growth rates are high, but also throughout life, as tissues are constantly undergoing repair and regeneration due to daily wear and tear or injury.

In addition to their primary role in tissue building and repair, proteins are involved in numerous other processes, such as enzymatic reactions, hormone production, and immune responses. However, the primary function highlighted in the question specifically focuses on the structural and repair aspects, which is why the answer emphasizing building new cells and repairing tissues is accurate.

While proteins can contribute to energy production and metabolic regulation, these are not their only or primary functions. Energy production from proteins typically occurs under specific circumstances, while metabolic regulation involves a range of nutrients, including carbohydrates and fats. Thus, the focus of the question aligns perfectly with the multifaceted roles proteins play, particularly in growth and repair functions within the body.