The outer mitochondrial is highly while the inner membrane is

The outer mitochondrial is highly permeable while the inner membrane is highly convoluted.

Explanation:

Permeable is that property of cell membrane which allows micromolecules to go inside or comes outside the cell. Mitochondria is the power house of the cell which is responsible for the production of energy from food molecules such as glucose. There are two parts of mitochondria i. e. outer mitochondrial membrane and inner mitochondrial membrane. The inner mitochondrial membrane is convoluted means folded many times.

substitution is the answer in this case