(c) : Parasitism is a relationship between two living organisms of different species in which one organism called parasite obtains its food directly from another living organism called host. The parasite spends a part or whole of its life either on or inside the body of the host. The general parasitic adaptations are (i) anaerobic respiration in internal parasites, (ii) loss of certain organs, (iii) presence of adhesive organs, (iv) excessive multiplication, (v) resistant cysts and eggs for safe transfer of their progeny to new hosts and (vi) well developed and complicated reproductive organs.