Why Aeroplane windows are round?

I am the fastest animal but cannot climb the tree. What am I?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

Can you fill the blank with the correct number?

6 30 870 756030 _____

Rectify the following equality 101 - 102 = 1 by moving just one digit.

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?

What begins with T, ends with T, and has T in it?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

Find out the missing number in the picture attached: