Do you have Any answer choices
Answer:
Four conditions are required for evolution to occur: reproduction, heredity, variation in fitness or organisms, variation in individuals among the members of the observed population.
There is only one main element involved in the fusion reactions inside the sun; Hydrogen, but if you need a second element then it is more than likely that the question is asking for the isotope of hydrogen that is called <span>deuterium.
So basically, Hydrogen and Deuterium; an isotope of hydrogen</span>
