Answer:
Much like the insulation around the wires in electrical systems, glial cells form a membraneous sheath surrounding axons called myelin, thereby insulating the axon. This myelination, as it is called, can greatly increase the speed of signals transmitted between neurons (known as action potentials).
Explanation:
for more pls visit
https://www.nature.com/scitable/topicpage/myelin-a-specialized-membrane-for-cell-communication-14367205/
Sand particles are known to move everywhere and are a part of the geosphere
I think the answer would be needs. Hope this helps.