( A ) none of the above
( B ) The neural organisation is very simple in lower invertebrates; for example, in Hydra it is composed of a network of neurons.
( C ) The neural system of all animals is composed of highly specialised cells called neurons which can detect, receive and transmit different kinds of stimuli.
( D ) The neural system is better organised in insects, where a brain is present along with a number of ganglia and neural tissues.
