Answer:
no unless u want that rona
Explanation:
its probably a kidnapper in a- agh nvm
Nerves allow us to feel things. So, the first two options are what nerves are responsible for.
The variable is the group that was given caffine, because thats what the doctors manipulated. They possibly altered the natural memory of the participants by giving them caffine. A more specific variable could be how much caffine each participant is given and what time are they given it.
Knock knock knock FBI open up lol