The myelin sheath on a neuron allows nerve impulses to be faster because

Axons with large diameters conduct impulse faster than those with small diameters. Also Myelinated axons conduct impulse faster than unmyelinated axons. Axons with the largest diameter are all myelinated, therefore they are capable of salatory conduction (Impulses jump from one myelinated node to another). The smallest diameter axons are unmyelinated, so their conduction is continuous.
I hope this helps. :) :)

Carbon-14 has a half-life of 5,730 years and most igneous rock is older than that.