I have an eye but still cannot see.

Who am I?

A man plots the murder of his wife. His plan is full proof. Nobody saw them leaving their house. He stabbed her with a knife while driving. She died on the spot. He threw her body in a valley. He threw the knife carefully wiping his finger prints on a random garbage bin. Then he went back to his home and no one was watching him this time as well.

After an hour, he was called by the local police department who informed him that his wife was murdered. They asked him to reach the scene of crime immediately. But as soon as he arrived at the crime scene, he was arrested by them.

How did the police know that he himself is the murderer?

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

What jumps when it walks and sits when it stands?

There are 3 apples in the basket and you take away 2. How many apples do you have now?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

When monkey rotate the gear, which mark will be hit 1 or 2 ?

See the given image carefully. What you have to do is move the blue checkers in the position of the black checkers and vice versa. You are only allowed to move the checker to an adjacent empty space. Do it in the least possible moves.

What kind of tree can you carry in your hand?

All of you like to eat me. I am a five-lettered word. Remove the first two and I turn into an infamous animal. Remove just the first and I become a heinous crime. Remove the first and the last and you can groove on me.

Can you guess who am I?