Explanation:
The cell is the basic unit of life
I would say for number three the answer would be 3
DNA is made of genes. so it is C
On one side of the grand canyon could be a squirrel with a birth defect witch reproduses with a squirrel with normal genes. But the birth defect is stronger than whatever trait that may be. so the litter of squirrels mostly have this trait. and the cycle contiues
