I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

A wooden log balances equally on the scales when weighed with three-quarters of a pound and three-quarters of a wooden log.

Can you calculate the weight of the entire wooden log?

He does not have any heart but still, He manages to live.
If you kill him, you will eventually die but yet you kill him.
He cannot run, who is He?

Can you find the missing piece of the Porsche?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

If you say my name, I will no longer exist. What am I?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.