A. (v) B. (iii) C. (ii) D. (i) E. (vi) F. (iv)
A. Amphibians possess dual habitat, i.e., they are found in both aquatic and terrestrial habitat. Their larva is completely aquatic and adult lives in terrestrial as well as in aquatic habitat
B. Mammals have mammary glands which produce milk and feed their young ones. The mammary glands are enlarged exocrine modified sweat glands functional in female mammals.
C. Chondrichthyes have the cartilaginous rod (notochord) in the young stage which is gradually replaced by cartilage.
D. Osteichthyes have air bladder which is a vesicle or sac containing air.
E. Cyclostomes possess sucking and circular mouth without jaws which is surrounded by tentacles and the tongue bears teeth. e. g., lamprey and nagfish.
F. Aves have light weighted bones with internal spaces filled with air called pneumatic bones and aerodynamic lungs with specialised air sacs. These are the adaptations which enable birds to fly.
