Animal Kingdom Question 115
115. Which of the following characteristic features always holds true for the corresponding group of animals?
(a) Cartilaginous endoskeleton $\hspace{5mm}$ Chondrichthyes
(b) Viviparous $\hspace{20mm}$ Mammalia
(c) Possess a mouth Chordata with an upper and a lower jaw $\hspace{5mm}$ Chordata
(d) 3 - chambered heart Reptilia with one incompletely divided ventricle $\hspace{5mm}$ Reptilia
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Answer : a
Hints & Solutions
(a) Chondrichthyes always have cartilaginous endoskeleton. Most mammals are viviparous, giving birth to young. However, the five species of monotreme, the platypuses and the echidnas, lay eggs. Chordates have jawless animals (Agnatha) as well. Most reptiles have 3 chambered heart. Crocodilians have 4 chambered hearts. Turtles have 3 chambered heart but with an incomplete wall in the single ventricle, so their hearts are functionally 4 chambered.
