The answer is D, photosynthesis and respiration.
—Evidence—
Oxygen is a byproduct of photosynthesis and, correspondingly, carbon dioxide the byproduct of respiration.
Oxygen gives our cells the ability to break down food in order to get the energy we need to survive. Although other animals may use different organs to breathe with, they all get oxygen into their bodies through respiration.
The water cycle is referred to as a continuous cycle because it repeats everyday. It's a cycle with no end.
<span>Oxytocin and antidiuretic hormone (adh) are synthesized in the ypothalamus but released from the posterior pituitary.</span>
Genes involved in production of abnormal red blood cells may have an abnormal sequence of bases (nucleotides), like inherited alteration in the gene for JAK2, a protein with enzymatic activity that's linked to the abnormal production of blood cells.
