The primary function of the glial cells is to:
a. insulate the axon and increase the speed at which neurons convey their message.
b. reduce the speed of neurotransmitters crossing the synaptic gap.
c. bundle the axons of neurons that produce the same neurotransmitters.
d. provide structural support and nutrition to the neuron.

The correct answer is d. provide structural support and nutrition to the neuron.

Explanation:

Glial cells are the cells that surround the neurons and provide structural support to them. They also help in insulation for neurons. They are the most abundant cells present in the nervous system.  

Many glial cell plays a role in providing nutrition and oxygen to the neurons and regulation of extracellular brain fluid. Glial cells also helps in cleaning up the dead neurons.  

The different types of glial cells are ependymal cells, schwann cells, microglia, oligodendrocytes, astrocytes, and satellite cells. So the right answer is d.

the correct answer is c   with the systems

helicase, i think thats it