I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

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?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

I don't get anymore wetter, no matter how much rain falls on me.

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.

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

How many letters are in the alphabet?

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"