(d) : Neuron (nerve cell) is one of the basic functional units of the nervous system. Neuron is a cell specialized to transmit electrical nerve impulse and so carry information from one part of the body to another. Each neuron has an enlarged portion, the cell body (perikaryon), containing the nucleus; from the body extend several processes (dendrites) through which impulses enter from their branches. A longer process, the nerve fibre, extends outward and carries impulses away from the cell body. This is normally unbranched except at the nerve ending. The point of contact of one neuron with another is known as asynapse