Which organelle is characteristically filamentous,cylindrical,or granular in shape?

Which was the first plant cell in which mitochondria were observed?

Read the statements $P$ and $Q$:
$P$: The number of mitochondria in each cell does not depend on the physiological activity of the cell.
$Q$: Mitochondria are present in both plant and animal cells.
Select the correct option from the given choices.

Cristae are formed by $..............$.

Cellular respiration is carried out by

Give scientific reason: Mitochondria is called the powerhouse of the cell.