Biology

The correct answer is: B.Lipids.

Explanation:

B.Lipids are used by the body for long-term storage of energy (in the form of fats) and also make up the structure of cell membranes (in the form of phospholipids). They are essential for energy storage and maintaining the structural integrity of cells.

A.Carbohydrates are primarily used for short-term energy and are not involved in long-term energy storage or membrane structure in the same way as lipids.