Oceans : 
    •     Sea animals like squid and octopus stay near the seabed and catch any prey that move towards them. When they move in water, they make their              body shapes streamlined.
    •     Generally aquatic animals have gills to help them use the oxygen dissolved in water. 
    •     Dolphins and whales do not have gills. They breathe in air through nostrils or blowholes that are located on the upper parts of their heads.This                    allows them to breathe in air when they swim near the surface of water. 
    •     They can stay inside the water for a long time without breathing. 

(ii)     Ponds and Lakes
    •     Roots of plants are much reduced in size and their main function is to hold the plant in place. 
    •     The stem is long, hollow and light.
    •     The stems grow upto the surface of water while the leaves and flowers float on the surface of water. 
    •     Some plants are totally submerged in water, i.e, all parts of the plant grow under water. These plants have narrow and thin ribbon like leaves.                      Through highly divided leaves, the water can easily flow without damaging them. 

•  Amphibious Adptations In Animals
    The animals which can live both on land as well as in water are called amphibious animals. Common amphibious animals are: frogs, toads and               salamanders.
       They have the following adaptations:
1.    The skin is moist and slimy which help in respiration.
2.    They can also respire through lungs.
3.    The hind legs are long and strong which help in hopping movements on the land.
4.    They have webbed feet for swimming.

C. Aerial or Volant Adaptations
        Animals which are adapted for the aerial mode of life (flying) are known as volant animals. Common volant animals are an birds and bats.
       They have the following adaptations:
1.    They have streamlined body which is covered with feathers.
2.    Their forelimbs are modified into wings.
3.    The bones are light, hollow, spongy and contain many air cavities.
4.    They have lungs for respiration.
5.    The nervous system and sense organs are well developed.
6.    The flight muscles are well-developed and their eyesight is very sharp.