Which of the following statements about myelin is not true? All axons have a myelin sheath. The myelin sheath is a factor in multiple sclerosis. Under a microscope, myelin is white in color. The myelin sheath affects the speed of neural transmission.

Option A is false.

All axon have myelin sheath.

Explanation:

Myelin sheath is a layer that surrond the nerve cells axon and provide insulation to the nerves. Myelin sheath are made up of protein and lipids.

Axon is a long projection of nerve cell that conduct electrical impulses away from the cell body. Not all axons are have myelin sheath

Axon can either be myelinated i.e is covered with Myelin sheath or unmyelinated. The myelinated axons are ensheathed along their length. The presence of myelin sheath on axons help to increase in speed of electrical impulses spreading all ng the myelinated fibre. Oligodendrocytes of Central nervous system and schawn cells of peripheral nervous system perform the function of producing myelin sheaths.

Examples of nerves without myelin sheath is the axons of group c nerve fibre.