Question #b813b

1 Answer
Jun 22, 2016

It is the theory that eukaryotic cells (eg. plants and animals) actually started out as different organisms that began 'working together' for the good of both of them.

Mitochondria are the best example - we believe that they were once separate organisms that got 'captured' by another cell to produce energy. In return they got a safe environment to live. This is supported by the fact that mitochondria actually have their own DNA.