In most of the invertebrates, kidneys are present for excretion.

Nearly 75% of the filtrate is reabsorbed by the renal tubules.

What happens due to the increase of sodium ions in the blood?

How many layers of glomerular epithelium are involved in the filtration of blood?

Which of the following is not a feature of a counter-current mechanism?

What is the normal amount of urea in the blood?

Which of these hormones acts as a check on the renin-angiotensin mechanism?

Which of the following is not a guanotelic organism?