The answer is D all of the above
The answer is C. species are the smallest taxonomic group. I also have taken this test before
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>
Answer:
i think it's D I hope this helps :)