Question

a) On a cool and wet day, large quantity of dilute urine is passed out by most people. Why?

b) Higher animals have always had elaborate excretory mechanism while higher plants do not have it. Explain why?

c) How does liver help in the process of excretion? [5 MARKS]

Answer 1

a) 1 Mark
b) 2 Marks
c) 2 Marks

a) On a cool and wet day, there is not much production of sweat, i.e. practically no loss of water through sweat. Therefore, the body loses water largely in the form of urine.

b) Higher plants have the ability to recycle the wastes and utilize them during anabolic process, which the higher animals can not do. Hence they need an elaborate mechanism to eliminate the wastes.

c) Liver manufactures bile pigments from haemoglobin of the dead red blood cells. Urea is formed in the liver from the harmful ammonium compounds and C$O_2$. Thus liver indirectly helps in excretion.