Why do we preferably have round manhole covers and not square ones?

I have teeth but i don't bite. Who Am I ?

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

Below, you can see some coding:
January = 1017
February = 628
March = 1335
April = 145
May = 1353
June = 1064
July = 1074
August = 186

Now deciphering the way it has been coded, can you find out how September will be coded?

Give it food and it will live; give it water and it will die.

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?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

The following "Brain Bat" means Slow Down.
S
L
O
W

Using the same logic, can you tell us what does the following Brain Bat means ?
E
V
I
G

What always comes into a house through the keyhole?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?