Terrestrial animals are generally either ureotelic or uricotelic,not ammonotelic. Why?

(N/A) Terrestrial animals are either ureotelic or uricotelic,and not ammonotelic. This is because of the following two main reasons:
$(a)$ Ammonia is highly toxic in nature. Therefore,it needs to be converted into a less toxic form such as urea or uric acid.
$(b)$ Terrestrial animals need to conserve water. Since ammonia is soluble in water,it cannot be eliminated continuously. Hence,it is converted into urea or uric acid. These forms are less toxic and also require significantly less water for excretion. This helps terrestrial animals conserve water.