Before Mount Everest was discovered, what was the highest mountain in the world?

How can you take 2 from 5 and leave 4?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

Can you name any English verb that becomes its past tense by simply rearranging the alphabets ?

How many letters are in the alphabet?

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary, you'd think nothing was wrong with it. Actually, nothing IS wrong with it. But it is not as ordinary as you might think. If you think about it for a bit, you will find out why it is truly so unusual. So what is it? What is so unordinary about this paragraph?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

How many letters are in the alphabet?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?