Why humans need organs, like the liver and pancreas, but amoebas do not.

They have no use for it, just like they dont have any type of respiratory organs like lungs.

Explanation:

In the case of nutrition and digestion they obtain food by capturing their prey with their pseudopodia. The food is internalized through a type of endocytosis known as phagocytosis. Nutrients are obtained as the enzymes digest the food inside the vacuole and when they are finished the food vacuole dissolves.

i am going to guess that it is co2.

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.