Question

Distinguish between: [5 MARKS]
(a) Excretion and Egestion
(b) Excretion and Secretion
(c) Vasodilation and Vasoconstriction

Answer 1

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

(a) Excretion is the removal of wastes like urea, uric acid unwanted salts etc. Whereas egestion is the removal of unabsorbed and undigested food in a decomposed form.

(b) Excretion is the removal of wastes from the blood, whereas the secretion is the absorption of waste substances in the blood. Secretion leads to the excretion.

(c) In vasodilation, there is an increase in the body temperature due to higher external temperature which dilates skin capillaries and more heat is radiated through sweating. Vasoconstriction results from decrease in the surrounding temperature and constriction of blood capillaries and as a result, sweat production decreases and loss of heat is prevented.