Answer:
What can you hold in your right hand but not in your left hand?
I am known for my natural tuxedo and marching
I am the minerals vital for your good health.
I am merry creature in pleasant time of year as in but certain seasons I sing that you can hear; And yet I'm made a by-word A very perfect mock; Compared to foolish persons And silliest of all folk.
I am a protector. I sit on a bridge. One person can see right through me while others wonder what I hide.
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?