What goes up but never comes down?

Can you name some countries which do not have the alphabet 'A' in them?

You need to complete the maze by entering from the entrance marked below in the figure near the yellow circle, bottom left and leaving from the exit point near the green circle, bottom middle.

Rule of Game: You can move only by exchanging green and yellow circles.

With the help clues provided in the image, can you find the 5 digit key?

A man is found hanging dead from the ceiling of a room. The room’s dimensions are 15 x 15 x 15. The man is only 6ft tall and the rope was only 2ft long. There are no windows and only one door to the room. The door is bolted shut from the inside, and a puddle of water is under the man. How did he kill himself?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

10+10 and 11+11 can give you the same answer.

Explain how?

You can find some missing letters in the picture. By placing two particular letters in the spaces, you can form a nine lettered word beginning from one of the corners and going clockwise direction to the middle. Can you find out the letters and the word?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?