Assertion : Nerve cells in coelenterata have complete co-ordination in their body.
Reason : True nerve cells occur for the first time in coelenate.

Options

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false

Answer

A

Explanation

Coelenterates possess a very primitive type of nervous system. In coelenterates, the separate mechanisms for digestion, respiration and excretion, reproduction etc evolved for the first time. Thus there is a constant need to maintain coordination between these systems. Nerve cells are developed for this purpose, for the first time in coelenterates.