The teacher told the student that if he told a lie then he will be expelled from school and if he told the truth then he still is expelled from school.

What can a student say to prevent his being expelled from school?

I know a nine-letter word having only one vowel.
Do you ?

A man was going to bleach his socks because they had gotten muddy the day before. As he was pouring the bleach into the washing machine, he spilt some on the floor. He got some cleaning fluid and mopped it up with a rag. Minutes later he was dead. What killed him?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

John went to buy some expensive, foreign chocolates. He only had Rs 100 with him. When he reached the shop, he got out and know that on those chocolates, there was a 15% import duty and 5% VAT.

How much worth chocolate should he buy so that he can accommodate it in Rs 100?

What has one eye, but can’t see?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

What am I?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?