Evolution of the atmosphere

Question 1

What happened in phase one?(first billion years)

Answer 1

Intense volcanic activity. This activity

released the gases that formed the early atmosphere and water vapour that condensed to form the oceans.

Question 2

What happened in phase two?

Answer 2

Green plants evolved and released O2. CO2 began to dissolve into oceans.

Question 3

What happened in phase three?

Answer 3

Oxygen builds up and creates the ozone layer. More complex organisms evolve.