An axon is a A) neuron's cell body. B) cluster of fibers at one end of a neuron. C) support cell in the nervous system. D) long, slim, tube-like structure extending from a neuron.

D) long, slim, tube-like structure extending from a neuron.

Explanation:

A neuron is a specialized cell which plays an important role in transmitting nerve signal or nerve impulse to other nerve cells. Neurons are made up of three parts mainly dendrites, cell body, axons.

Dendrite accepts the signal from another neuron, axon is long, thin and slender nerve cell projection that transfers electric impulse from the cell body towards axon terminal. Then from the axon terminal, the nerve impulse is released to another neuron. Therefore the correct answer is D.

a- all cells come from pre-existing cells