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>
Prokaryotes do not have membrane bound organelles, but eukaryotes do.
I think they are good and bad
Answer:
The definition of trade off is an exchange where you give up one thing in order to get something else that you also desire. An example of a trade off is when you have to put up with a half hour commute in order to make more money.
Explanation:
The HCG hormone is the answer possibly
