Question

Which of the following characteristic features always holds true for the corresponding group of animals?

(a)	Possess a mouth with an upper and a lower jaw	Chordata
(b)	3–chambered heart with one incompletely divided ventricle	Reptilia
(c)	Cartilaginous endoskeleton	Chondrichthyes
(d)	Viviparous	Mammalia

Answer 1

Ans: (c) 3–chambered heart with one incompletely divided ventricle - Reptilia

Sol: Phylum Chordata includes both jawless vertebrates (Agnatha) and jawed vertebrates (Gnathostomata). Crocodile of Class Reptilia has four chambered heart with two auricles and two ventricles. Duck billed platypus and spiny anteater are oviparous mammals.