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>
Contain structures that regulate and perform life functions.
Genetic predisposition to an inherited disorder an increased likelihood of developing the particular <span>disea</span>se<span> based on a person's </span>genetics.<span>
Genetic testing for predisposition to an inherited disorder in a minor child would be considered reasonable </span>when the risk is high and prophylaxis to reduce disorder severity is available.
I'm almost sure your answer is going to be "Because the sun's mass creates a gravitational force that pulls earth towards it."
correct me if I am wrong.