Until Recently, We Only Described Neurons as Cellular Units of the Nervous

Until recently, we only described neurons as cellular units of the nervous system. Which is a probable reason science overlooked the importance of neuroglial cells?

A) Neuroglial cells have long processes and look just like neurons.
B) Neuroglial cells are rare compared to neurons and make up a very small volume of the brain.
C) Neuroglial cells were thought to merely support neurons and their complex chemical role was not yet detected.
D) Neuroglial cells are distant from the other neuron tissue.
E) Neuroglial cells are developing larger today as people use more memory.