List the adaptations seen in terrestrial animals.

Explanation

(i) Animals like earthworm and land Planarians secrete a mucus coating to maintain a most situation for burrowing, coiling, respiration etc.
(ii) Arthropods have an external cover, the respiratory surfaces and well developed tracheal systems.
(iii) In vertebrate skin, there are multicellular layers, preventing loss of water.
(iv) In some animals, the water loss through excretion is compensated by water obtained through food.
(v) During drought season, birds rarely breed. They breed before rainy season so that there is availability of abundant food.
(vi) The camels are adapted to regulate water for evaporative cooling through the skin and respiratory system. They excrete highly concentrated urine. They can also withstand dehydration upto 25% of its body weight.