a variable is the right answer
Glycolysis, Krebs cycle, electron transport chain, oxidative phosphorylation
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)
The answer would be Linnaeus primarily used physical characteristics.
