why number 8549176320 is one of a kind?

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 ?

Astrology starts with the alphabet A, Biology starts with B, Psychology with P and Limnology with L.

Can you find an "ology" that begins with a P?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

What brings you down but never up?

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

Who are the happiest people in IPL match?

While going to your grandmother's house, you counted Twenty houses on the right side. While returning back to your home, you counted Twenty houses on the left side.

How many houses are there between your home and your grandmother's home?

Solve the alphametic puzzle by replacing the alphabet with the number.

S T O R M +
S O L E S
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T O W E L
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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?