What does this simple rebus mean?

I am lying and I always lie. Tell me whether I am lying or telling the truth.

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

How could a baby fall out of a twenty-story building onto the ground and live?

You can see it everyday, But cannot touch it at will. What is it?

Two old friends, Jack and Bill, meet after a long time.

Three kids
Jack: Hey, how are you, man?
Bill: Not bad, got married and I have three kids now.
Jack: That's awesome. How old are they?
Bill: The product of their ages is 72 and the sum of their ages is the same as your birth date.
Jack: Cool..But I still don't know.
Bill: My eldest kid just started taking piano lessons.
Jack: Oh, now I get it.

How old are Bill's kids?

A boy collects white seashells from the sea and brings them home every night. When he has enough of them, he decides to sell them to a trader.

The trader is ready to buy the shells and he asks the boy about the quantity. At this, the boy starts calculating. He has a giant box that contains 3 mini boxes. Two of them have another mini box inside. If the giant box can hold 50 shells, how many brown shells can he sell to the trader?

What 8 letter word can have a letter taken away and it still makes a word. Take another letter away and it still makes a word. Keep on doing that until you have one letter left. What is the word?

Where do you go to learn how to make ice cream?

What Adam and Eve do not have but the rest of the people have?