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>
Because if there is a minimal variation of it the normal state of pH, it can cause severe effects in the brain, arteries, the heart, and other organs.
In other words, it can have some serious effects on the body systems that can lead big diseases, like cancer.
Endoplasmic reticulum is the answer.
Base on one of the Law of Thermodynamics, the amount of available energy decreases whenever energy is changed in form (which includes a transfer from one trophic level to another). So, as we go from the first trophic level to the top trophic level, the amount of available energy becomes less and less.
