Circular and double-stranded $DNA$ is found in:

The function of the $Mitochondria$ is .....

The figure below shows the structure of a mitochondrion with its four parts labelled $A, B, C$ and $D$. Select the part correctly matched with its function.

In the given figure of an animal cell, one organelle is marked as $A$. Select the correct identification and function of the organelle '$A$' from the given options.

Folding of the inner membrane of mitochondria are called

What do the cristae in mitochondria contain?