Question

NCERT VI Social Sciences

Give reasons

(a) Even when the water at the surface of a lake is frozen, aquatic animals continue to live below the ice.
(b) It is easier to swim in sea water.
(c) Water is said to be a universal solvent.
(d) Water is an ideal medium for chemical reactions.

Answer 1

In places like poles water is frozen but sill the marine animals continue to live the reason is due to less temperature surface water gets frozen.As we know density of ice is lees than water and frozen water i.e.,ice floatson water.Animals in polar regions adapt themselves to the surrounding environment and the live underneath water.

Answer 2

(a) because water under the thin sheet of remains on constant temperature of 4 degree Celsius and some animal are adapted to the environment
(b) because salt makes water denser and heavier
(c) because water has capability of dissolving more substance than any other         liquid   
(d) because of following properties
     1) neutral pH level  
     2) high specific temp 
     3) it is universal solvent