for plants and other organisms to develop differences among their respective species the alleles of their genes must contain variations. what is the original source of these variations?

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen

When a human or animal consumes food, the carbon in that food is most likely to be converted into which of the following elements? a. carbon remains carbon b. nitrogen c. oxygen d. hydrogen

What happens during the experiment stage of the scientific method