Question

Imagine you are sitting in a very quiet room when suddenly behind you there’s a very loud bang, like a firecracker exploding.

Answer 1

Answer:

A. I would be startled by the sudden noise and would probably take cover some wheres. B. My nerves in my ears would send a signal to my brain causing my twitching muscle fibers to react quickly and heart might stop for a moment.  C. The heart rate would increase the brain would be aware that there may be more sudden noises or events your adrenaline would be pumping and your quick twitch muscle fibers would probably be tense or contracted ready to make quick sudden movements if necessary and your hairs would stick up i guess as extra senses for if something would touch you.  

Explanation:

not to mention but by the time you are startled your senses would probably be heightened due to you being  aware of your surroundings such as you would be constantly looking around you would hear better and probably move quicker for a short period of time due to pumping adrenaline.