What is in seasons, seconds, centuries and minutes but not in decades, years or days?

A very interesting trivia question for all.

Why do men's shirts have their buttons on the right side and women's have buttons on the left-hand side?

I cannot talk, but I always reply when spoken to. What am I?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

I have teeth but i don't bite. Who Am I ?

If a shopkeeper can only place the weights on one side of the common balance. For example, if he has weights 1 and 3 then he can measure 1, 3 and 4 only. Now the question is how many minimum weights and names of the weights you will need to measure all weights from 1 to 1000? This is a fairly simple problem and very easy to prove also.

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

What is the centre of gravity?