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.

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

What can you catch but never throw?

I taste better than I can smell. Who am I?

A man is found unconscious in front of a store at two in the morning. His head is bleeding and there’s a brick laying next to him. When the police arrive, they carry the man to jail. Why did they arrest him?

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

What you cannot hold but it is yours?

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

A blonde put eyeliner on her head. Why?

Can you find out which number multiplied by itself will give the output as 12345678987654321?