Answer:
c) degree of myelination of the axon
Explanation:
The myelin sheath covers many axons in central nervous system (CNS) ( by oligodendrocytes) and in the peripheral nervous system (PNS) (by Schwann cells). Their function is to insulate axons and to increase the speed at which information travels from one nerve cell to another.
Nerve conduction velocity is specific to each individual and depend on the level to which that axon is myelinated, but also on an axon's diameter.
Answer:
a. Mammalia
Explanation:
Mammalia are the class species that have distinct systems and separate ducts for different activities like reproduction, excretory, and defecatory and moreover they have nipples to feed their young ones.
So, the above species which has a single duct for reproductive, excretory, and defecatory material as well as a lack of true nipples does not belong to Mammalia
That way they can get the average result and they're usually more accurate.