Answer:
I am an odd number. Take away a letter and I become even. What number am I?
Goes over all the hills and hollows, Bites hard, but never swallows.
Teenage girls are pros at creating me. Learn me in classes.
I can generate fear and some say I come out of your ears. I am as quiet as a mouse but not welcomed in the house.
I'm orange when long I'm white when short. What am I?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.