Nuclear forces, according to my textbooks! Hope this helps!
The transmission of an impulse is made possible first by electric signals propagating within a neuron. Then, at the end of the axon called a synapse, chemical substances called neurotransmitters get released to transmit the message. These neurotransmitters then attach to chemical receptors in the following neuron.
This means that a single carbon atom can form up to tetravalent bonds with other atoms
Base substitutions, deletions and insertions.