Nuns???

I live in Houston (a cultural melting pot supposedly) and rarely do I see strange things that make me go hmmmmmmmm. But lately on my way to work, I've been seeing a nun. Yes a nun. She is always standing at a Metro bus stop dressed in a solid white habit. The first couple of times that I saw her, I thought maybe it was a nurse uniform. After a closer look (I actually changed lanes to see her) I confirmed that she was indeed a nun.

So this raised several questions:

#1) Where does this nun live?
#2) Are there more nuns close by? Do they share a house/apartment?
#3) What kind of job does she have that she takes the bus?
#4) Why is her habit white and not black/white?

I'm not Catholic so I don't know much about nuns, priests, etc, but I just thought it was a strange occurence to see on my way to work periodically. Maybe one day I'll pull over and just ask...