Uricotelic mode of excreting nitrogenous wastes is found in

How much urea is excreted per day?

Give examples of ammonotelic animals.

Aquatic reptiles are

Ornithine,an amino acid,is found:

The characteristic that is shared by urea,uric acid and ammonia is/are:
$(A)$ They are nitrogenous wastes.
$(B)$ They all need very large amount of water for excretion.
$(C)$ They all are equally toxic.
$(D)$ They are produced in the kidneys.