I am a cell. I am long and thin. I reach all the way from the brain to the tip of a finger. I have a special coat of fat that helps me do
my job. My job is to send electrical signals from one part of the
body to another.

Neurons

Explanation:

We humans have a nervous system that coordinates our behavior and transmits signals between different parts of our body.

Now, this nervous system contains a lot of nerve cells which we call Neurons. These Neurons have a cell like body and their job is to transmit signals from one part of our body to another.

Thus, the cell is called Neurons.

explanation:

the masses of the objects and the distance between them