How do the oxygen (O2) and carbon dioxide (CO2) levels change over time?
What is always true about the total amount of O2 and CO2 in the test tube?
What happens when the CO2 reaches zero?

Respuesta :

Answer:

Over a vast amount of time, millions of years, the earth gradually cooled. When the temperature dropped enough, water vapor condensed and went from a gas to liquid form. This created clouds. From these clouds, the oceans formed and the oceans absorbed a lot of the carbon dioxide in the atmosphere.

Explanation:

ACCESS MORE