Inside a mitochondrion, the space surrounded by the folds of the inner membrane is the:

1. A mitochondrion has two membranes, and the inner one is heavily folded. 2. That creates two distinct compartments. 3. The space between the two membranes is the intermembrane space. 4. The area surrounded by the folds is called the mitochondrial matrix. 5. Stroma belongs to the chloroplast, so it is the trap here. _Source: OpenStax Biology for AP(R) Courses (CC BY 4.0), Ch 4 'Cell Structure', sections 4.1-4.6_