Nervous System—Learning about Reactions

When my partner threw the ball at me when I held the overhead transparency in front of me, I flinched. This protects my eyes by closing them, and not keeping my eyes vulnerable. I  think the nervous system responded the same way as a ruler experiment we did because they were both a sort of flinch: When you heard the "go" or felt a tap in the ruler experiment your nerves told you to grab, and in this experiment your nerves told you to close your eyes when you saw the ball being flung at your head.