Question

Which among the following is incorrect about nervous system in Echinodermata?

(a) Radial nerves extend through the arms from the central nerve ring that surrounds the mouth

(b) Sensory tentacles help in sense of touch

(c) Epidermis contains sensory cells that help in sense of touch

(d) Their brain is made up of 4 nerve rings

The question was posed to me during an interview.

My question is from Classification of Animal Kingdom into Different Phylum-4 topic in chapter Animal Kingdom of Biology – Class 11

Answer 1

Correct answer is (d) Their brain is made up of 4 nerve rings

Best explanation: Radial nerves extend through the arms from the central nerve ring that surrounds the mouth. Sensory tentacles help in sense of touch. Epidermis contains sensory cells that help in sense of touch. In Echinoderms, brain is absent.