Answer- you would use a Punnet Square to cross the kinds. In order to know which ones to use, you'd have to test them all. Without knowing what each letter codes for it is hard to show
Internal means its on the inside
external means its on the outside
so an internal regulator is when the proteins respond to events on the inside of a cell
and an external regulator is when the proteins respond to events outside the cell
A sudden inrush of water could over whelm animals and possibly kill them if the water is of a different type.
