It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?

What do you get if you add 2 to 100 four times?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

The pound is not a finish.

We are sharing a few instructions below, which you have to use in any suitable order to modify the above sentence such that the end sentence is a scientific fact.

- Eliminate a letter and supplement another in its place.
- Take away one word.
- Remove one letter from one word.
- Get rid of two letters from one word.
- Swap a word with its antonym.

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