Answer:
innervation of the sympathetic nervous system
Explanation:
Based on the information provided within the question it can be said that this lower urine output is primarily due to innervation of the sympathetic nervous system. This supply of nerves then increases the pressure which tightens the afferent arteriole, and is what prevents urine from passing through. Hence why the urine output is only 4 mL over the first hour on arrival.
Evolution does not occur in a straight line with one species another in a series of orderly steps with living species that are closely related share a common trait. I hope my answer has come to your help. God bless and have a nice day ahead!