A. external
These types of signals are observed when there is a cut on the body. The epidermal cells lose contact with one another and divide faster until they are in contact once again. After they come into contact, division slows down again.
Less common because they would look even differently than a normal person because the mutation.
The answer would be C because when you have a magnet the further u get from the magnetic item the weakest it will get but the closer you get to the magnetic the stronger it gets.
The answer your looking for is c hope it helps
and #rateme