What has many keys but can’t open a single lock?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

I make two people out of one. What am I?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

Which is the correct shadow of the bird?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

Three ants are going up a hill, one behind the other. The last ant then says to the other ants, 'There is an ant behind me!'' How come?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?