I’m tall when I’m young, and I’m short when I’m old. What am I?

I am an eight letter word and I am a computer terminology.
The second, third and fourth letters make an animal.
The fourth, fifth, sixth, seventh and eighth letters make a weapon.
The first, second, third and fourth letters can be taken as an outcome of any exam.
The fifth, sixth, seventh and eighth letter combine to form a high end typing software.

Can you tell who am I ?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

I am a word of 12 alphabets.

* Alphabets 12, 4, 7, 2, 5 : Eastern beast of burden
* Alphabets 1, 8, 10, 9 are street made famous by Sinclair Lewis.
* Alphabets 11, 3, 6 are past.

On whole it means a person suffering from delusions of greatness.

What Is it ?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

Who has married many women but was never married?

I am a five-letter word and people eat me. If you remove the first letter I become an energy form. If you remove the first two letters, I am needed to live. Scramble the last three letters and I am a drink. What word am I?