Insects are

The yellow colour of urine is due to the presence of

Uric acid is $P$ and therefore requires $Q$ amount of water for its excretion.

Which of the following organisms has uric acid as the main nitrogenous waste product?

In aquatic organisms,the end product of nitrogen metabolism is:

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.