What is harder to catch the faster you run?

Why do people go to bed?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Decode below rebus
D
N
A
T
S , D

John was so frustrated to be the suspect of being a sleeper terrorist that he shoot himself right between the eyes with a revolver in his toilet. The revolver and the bullets were accurate. Minutes later John walks out of the toilet unharmed.
How can this be possible?

Buy me, smell me or deliver me, I do not change.

Who am I?

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

What can you see in the middle of March and April that you can never see in any other month?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?