I travel all around the world but always stay in the corner. What am I?

How can you tell a raw egg from a hard-boiled egg?

In particular commonwealth games, a female participant won silver and gold medals for a single event.

How can this be possible?

The host of a game show, offers the guest a choice of three doors. Behind one is a expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

Who is that with a neck and no head, two arms and no hands? What is it?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

What has lots of eyes, but can’t see?

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?