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
These preparations are called Vaccines. A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing micro-organism and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins.
A symbiotic relationship in which one organism can take
advantage and the other is not harmed The treehopper-ant mutualism becomes
parasitic in years when spiders are rare, because the treehoppers no longer
derive a large benefit but pay a fitness cost.
What the other person said!
