No that is just, no just no. DNA is copied through cell reproduction where a cell splits to create more (growing for multi called organisms and asexual reproduction for single celled organisms) The mitochondria is an organelle that is the "power house" of the cell, the "digestive system".
Blood platelets... I think are red blood cells, I know we have red and white... hmmm... hope that helps
As you grow father away from the mid ocean ridge the rock is older as you get closer the rock is younger
