1. (i) It is necessary to maintain a normal osmotic concentration of the blood.   2. (ii) People on reaching high altitude may suffer from unsteady vision, loss of hearing, lack of muscular co-ordination and even complete blackout.   3. (iii) Salt and sugar are used in preserving food.   4. (iv) A tiger owes its existence to chlorophyll.   5. (v) Some plants show wilting of their leaves during mid day even when the soil is well watered.   6. (vi) On sprinkling common salt on grass growing in a lawn, the grass is killed.