What is the center of gravity? - Riddle Time

Who spends the day at the window, goes to the table for meals and hides at night?
Show Answer            Hide AnswerA fly.

 

Each time you take a step you make one of me, but then you leave me behind. What am I?
Show Answer            Hide AnswerA footprint.

 

What building has the most stories?
Show Answer            Hide AnswerA Library

 

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?
Show Answer            Hide AnswerA river.

 

You can see nothing else When you look in my face, I will look you in the eye And I will never lie. 
Show Answer            Hide AnswerYour reflection

 

Everyday I stalk you all day long,With every move you make, I never make one wrong.I vanish twice a day with the sun's height and fall, I will follow you anywhere, even the bathroom stall. What am I?
Show Answer            Hide AnswerYour shadow.

 

A man has 3 children and half of them are girls, how is this possible?
Show Answer            Hide AnswerAnswer: They are all girls (technically 2 or 3 must be girls).

 

What is the center of gravity?
Show Answer            Hide AnswerV.

 

Why don't mountains catch colds?
Show Answer            Hide AnswerThey have a snow cap.

 

What never gets any wetter no matter how hard it rains?
Show Answer            Hide AnswerThe ocean.