Final answer:
Conduction speed in neurons is enhanced by myelination, as it allows for saltatory conduction, and by increasing temperature, which raises the rate of nerve impulse propagation. Myelin sheaths act as insulators and temperature affects the diffusion rates of ions.
Step-by-step explanation:
The speed at which an action potential is conducted along an axon in a neuron can be influenced by a number of factors. Myelination is a crucial factor; it involves the presence of a myelin sheath around the axon, which acts as an insulator to prevent current leakage and thus increases the speed of action potential conduction through saltatory conduction. This is because the action potential 'jumps' from one node of Ranvier to the next, where the nodes are gaps in the myelin sheath and contain a high density of voltage-gated Na+ channels that regenerate the action potential.
Another factor that can enhance the speed of conduction is the temperature. Generally, an increase in temperature can increase the speed of nerve impulse propagation, up to a certain point before the proteins within the neuron begin to denature and affect the function negatively.
Thus, the correct answers that enhance conduction speed are A) myelin and C) increasing the temperature.