With which system are dendrites associated?

Which of the following statements is correct about the nodes of Ranvier?

Select the correct option for dendrites and axons.
$I -$ Short fibers,$II -$ Long fibers,$III -$ Transmit impulses away from the cell body,$IV -$ Transmit impulses towards the cell body,$V -$ Highly branched fibers,$VI -$ Unbranched fibers
Dendrites $\quad$ $\quad$ Axon

How does an unmyelinated axon differ from a myelinated axon?

Nissl bodies are mainly composed of

In which of the following are the medullated (myelinated) nerve fibers $NOT$ found?