the parasympathetic nervous system stimulates the secretion of diluted saliva. The nervous center for this reflex is the superior salivatory nucleus in the pons for sublingual and submandibular glands(seventh cranial nerve-facial), and the inferior salivatory nucleus for parotid glands(ninth cranial nerve-glossopharyngeal nerve)
Answer:
carbon, hydrogen, nitrogen, and oxygen
Essentially, a control variable is what is kept the same throughout the experiment, and it is not of primary concern in the experimental outcome. Any change in a control variable in an experiment would invalidate the correlation of dependent variables (DV) to the independent variable (IV), thus skewing the results.