Which of the following are uricotelic animals?

Which of the following pairs of excretory substances are removed from the blood during the Ornithine cycle?

The major excretory product of arthropods is

Urea in human urine is derived from the breakdown of:

The characteristic that is shared by urea,uric acid and ammonia is/are:
$I.$ They are nitrogenous wastes.
$II.$ They all need very large amount of water for excretion.
$III.$ They are all equally toxic.
$IV.$ They are equally in the kidneys.

The products of protein catabolism are .....