Which structure of the excretory system in humans is responsible for converting ammonia into urea?

a. liver
b. lungs
c. skin
d. kidneys

A. Liver

Ammonia is a toxic byproduct of metabolic activities occurring in the human body. The ammonia is converted into urea a less harmful metabolite by mitochondrial cells of liver. The urea enters into the blood circulation. The blood containing urea is filtered by kidney and excreted along with other components of urine.

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

dont know just give me brainliest