The primary energy source for an organism is d) carbohydrate.
Carbohydrates are the main fuel for our bodies. They are converted into glucose, which is then used by our cells to produce energy. Although fats and proteins can also provide energy, carbohydrates are typically the body’s first choice, especially during high-intensity exercise. They are found in foods such as breads, fruits, and vegetables and are essential for optimal muscle function and overall energy levels.