Answer:
The addition and response to the net effect of postsynaptic potentials is called Spatial summation
Explanation:
Signal summation occurs when impulses received by a neuron are eummed together to reach the excitation threshold to fire a neuron. It occurs at the axon hillock of a neuron. Signal summation occurs since each neuron is connected to many other neurons, often receiving multiple impulses from them, both excitatory and inhibitory.
Signal summation can either be temporal or spatial.
Temporal summation, occurs when impulses received at the same place on the neuron in close temporal succession add up to initiate an action potential in the neuron.
Spatial summation occurs when impulses received simultaneously at different places on the neuron add up to initiate an action potential in the neuron.
Having two copies of the mutated genes cause sickle cell anemia, but having just one copy does not, and can actually protect against malaria - an example of how mutations are sometimes beneficial.
The majority of mutations have neither negative nor positive effects on the organism in which they occur. These mutations are called neutral mutations. Examples include silent point mutations. They are neutral because they do not change the amino acids in the proteins they encode.
Hope this helped :)