A(n) neuron has one axon and one dendrite extending directly from the cell body.
unipolar
bipolar
multipolar
pseudounipolar

bipolar

Explanation:

Neurons are highly excitable cells that communicate with each other or with other effector cells, using basically electrical language. Most neurons have three regions responsible for specialized functions: cell body, dendrites, and axons.

Most neurons have several dendrites and one axon, so they are called multipolar. But there are also bipolar and pseudo unipolar neurons. In bipolar neurons, two extensions leave the cell body, one dendrite and one axon.

the scientific method.

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!