The natural cycling of oxygen between organisms and their environment is most directly accomplished through which
ofthe following pairs of processes?

a. the production of carbon dioxide through the process of photosynthesis

endo:

regulates body hormones, aldosterone, vasopressin

neural:

signal, regulates body using electric signals, reflex

endo has to do with hormones; aldosterone and vasopressin are both hormones. i also had this question and got it right : d