Question

The exoskeleton is absent in:

• A. (i), (ii)
• B. (ii), (iii)
• C. (i), (iii)
• D. (ii), (iv)

Answer 1

The correct option is D

(ii), (iv)

The correct option is D

Explanation of the correct option:

1. Exoskeleton is an external skeleton that helps in supporting and protecting an animal's body.
2. Frogs and toads don't have exoskeletons because they are vertebrates with an evolved endoskeleton which is made of a series of internal bones.
3. Hence it is absent in the frog and toad due to which their skin is smooth and soft.

Explanation of the incorrect option:

Option A:

1. Fishes have the exoskeleton of dermal scales.
2. Their exoskeleton is made up of either bone or cartilage.
3. Frogs don't have exoskeletons because they are vertebrates with evolved endoskeletons.

Option B:

1. In Rabbits, an exoskeleton is present as nails, claws, and hairs.
2. Frogs don't have exoskeletons because they are vertebrates with evolved endoskeletons.

Option C:

1. Fishes have the exoskeleton of dermal scales.
2. In Rabbits, an exoskeleton is present as nails, claws, and hairs.

Final answer: The exoskeleton is absent in frogs and toads.