Question

which source of energy is ideal for prolonged, low - intensity activity?
lipids
protein
glycogen
lactic acid

Explanation:

Lipids are a long - term energy storage molecule. During prolonged, low - intensity activity, the body can efficiently break down lipids (through processes like beta - oxidation) to provide a sustained supply of energy. Protein is mainly for building and repairing tissues and is not the primary fuel for such activities. Glycogen is a short - term energy store (stored glucose) and gets depleted relatively quickly. Lactic acid is a by - product of anaerobic metabolism (not the energy source itself) and is associated with high - intensity, short - term activities.

Answer:

lipids