Question

Crocodile shark and penguin are similar to whale and dogfish, in which one of the following features?

• A. Have gill slits at some stage.
• B. Possess a solid single stranded central nervous system.
• C. Lay eggs and guard them till they hatch.
• D. Possess bony skeleton.

Answer 1

The correct option is A Have gill slits at some stage.

• Animals belonging to phylum Chordata are fundamentally characterized by the presence of a notochord, a dorsal hollow nerve cord and paired pharyngeal gill slits. Crocodile, penguin, whale, and dogfish are all chordates. All of them have gill slits or have had it at some stage of embryonic development. Thus, paired gill slits are present in these animals at some stage of life.
  
• Hence crocodile shark and penguin are similar to whale and dogfish have gill slits at some stage.
• So, the correct answer is 'Have gill slits at some stage'.