Riddles
100

I'm lighter than air but a hundred people cannot lift me. Careful i am fragile! what am i?

A Bubble

200

What goes up and down but doesn't move?

A Staircase

300

What starts with "T" ends with a "T" and has "T" in it.

A teapot with tea in it

400

What begins with an "e" and ends with an "e" and only has one letter in it?

An envelope! 

M
e
n
u