the particular condition that someone or something is in at a specific time.
The answer is the 4th phrase.
The main function of the myelin sheath is to insulate the axons of the neurons (the fourth opton).
As it does that, it also speeds the transmission of the impulses:without it, the transmission would be slower (second option)
Ps. Multiple sclerosis is the illness of the myelin sheath
Explanation:
A vaccine is a substance that helps protect against certain diseases. Vaccines contain a dead or weakened version of a microbe. It helps your immune system recognize and destroy the living microbe during a future infection.
