The correct answer to this question is this one: they lacked oxygen. The earliest organisms were completely heterotrophic in nature because of the reason that they lacked oxygen. <span>A heterotroph is an organism that cannot fix carbon and uses organic carbon for growth. </span>
A, the others are unrealistic speeds.
Answer:
cell membrane
Explanation:
There are thousands of proteins embedded in the cell's lipid bilayer
86 degrees fahrenheit or 30 degrees celsius
... whereby the body procedures glucose from amino acids and glycerone molecules
