What caused the creation of mitochondria? A. One cell took over another cellb. Life forms became more complicatedc. Cells needed more energyd. DNA was shared between cells

A. One cell took over another cell

Explanation:

Mitochondria is an organelle present in a eukaryotic cell that performs the function of producing ATP molecules from the available substrates in the cell.

The mitochondria organelle has its DNA other than the cellular DNA which shows that it was once an independent organism. This was proved by the endosymbiotic theory that during the formation of the eukaryote cell, the proto-eukaryote engulfed the chemosynthetic bacteria which later formed the symbiotic relationship with the cell and evolved into the mitochondria.

Thus, Option-A is the correct answer.