Question

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

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

Answer 1

The correct option is D

Have gill slits at some stage

The correct option is D.

Explanation of Correct option:

1. Ernst Haeckel coined the phrase “Ontogeny repeats phylogeny” which states that the development of an organism (ontogeny) reflects its evolutionary history (phylogeny).
2. Crocodiles, penguins, whales and dogfish are all chordates.
3. Therefore all of them possess gill slits during a stage in their early development.

Explanation of Incorrect option:

Option A:

The whale is a mammal so it gives birth to young ones and does not lay eggs.

Option B:

Dogfish belongs to the class Chondrichthyes, it possesses a cartilaginous skeleton and not a bony one.

Option C:

Chordates are characterised by the presence of a hollow nerve cord and not a solid central nervous system.

Final answer: Crocodiles and penguins are similar to whales and dogfish in having gill slits at some stage.