What does does this rebus picture means ?

What has many teeth, but cannot bite?

Outside a tattoo artist's shop, there was a signboard which read 'I make tattoos on only them who do not tattoo themselves'.

Reading it what do you think, does the tattoo artist tattoo himself?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

What is wrong in the below Picture?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

What is the largest number you can write with just 3 digits?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

When can we add 2 to 11 and get 1 as the correct answer?