Answer: The cristae increase the surface area of the inner membrane and enhance the mitochondrion's ability to produce ATP through the process of cellular respiration.
Explanation: For example, the inner membranes in liver cell mitochondria are folded in such a way that their surface area is about five times greater than the surface area of their outer membranes. Cells that require a lot of ATP (e.g., muscle cells) possess an even greater number of folds.