Final answer:
Carbohydrates provide structural support and long-term energy, proteins provide building materials, and fats are essential for vitamin absorption.
Step-by-step explanation:
Carbohydrates provide structural support and are a source of long-term energy. Proteins are not the body's primary energy source, but rather provide building materials for the body, such as amino acids. Fats are essential for vitamin absorption and play a role in energy storage.