May have formed the oxygen released into the early atmosphere.

Cyanobacteria or simply known as blue-green algae may have formed the oxygen into the early atmosphere. This is because these micro-organism has the capability to photosynthesize wherein they can produce oxygen and carbohydrates. In fact, all the plants contribute in the fomation of oxygen.

The answer would be dogs.

The punnett square is the device used to predict genetics.