Which are the basic structural and functional units of the nervous system?

1. Axons
2. Nephrons
3. Neurons
4. None of these

Neurons, or nerve cells, are the fundamental units of the brain and nervous system. They are responsible for receiving sensory input, sending motor commands to muscles, and relaying electrical signals at every step in between. Axons are parts of a neuron, and nephrons are the functional units of the kidney.