Select the correct option:
$(1)$ The cell body contains typical cell organelles and Nissl's granules / neurotransmitters.
$(2)$ The nervous system of Hydra is composed of a nerve net / ganglia.

(A) $(1)$ The cell body (cyton) contains typical cell organelles and Nissl's granules. Nissl's granules are rough endoplasmic reticulum with ribosomes,which are sites of protein synthesis.
$(2)$ The nervous system of Hydra is composed of a nerve net. It is a primitive type of nervous system consisting of a network of neurons spread throughout the body,lacking a centralized brain or ganglia.