Answer:
Cristae
Explanation:
Mitochondria are bounded by two lipoprotein membranes similar to other cell membranes. While the outer membrane is smooth, the inner membrane has numerous folded layers - called mitochondrial ridges - that protrude into the interior of the organelle.
The internal cavity of the mitochondria is filled with a fluid called the mitochondrial matrix, where several enzymes are present, in addition to DNA and RNA and small ribosomes and substances necessary for the manufacture of certain proteins.
