Q. Crocodile and penguin are similar to Whale and Dogfish in which one of the following features?
A) Possess a solid single stranded central nervous system
B) Lay eggs and guard them till they hatch
C) Possess bony skeleton.
D) Have gill slits at some stage
Explanation
[Solution from source] All four are chordates, and every chordate has pharyngeal gill slits at some stage of its life, at least in the embryo. Chordates have a hollow dorsal nerve cord, not a solid one; the dogfish has a cartilaginous skeleton and the whale is viviparous, so the other features are not common to all. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.