What does the below rebus riddle means?

There were two grandmothers and their two granddaughters.
There were two husbands and their two wives.
There were two fathers and their two daughters.
There were two mothers and their two sons.
There were two maidens and their two mothers.
There were two sisters and their two brothers.
Yet there are only six, who are buried here,
All are born legitimate and relationships clear.
How can this happen?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

A thief enters a store and threatens the clerk, forcing her to open the safe. The clerk says, “The code for the safe is different every day, and if you hurt me you’ll never get the code.” But the thief manages to guess the code on his own. How did he do it?

Find the missing letter in the last circle logically in the given below picture.

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

What word begins and ends with an E, but has only one letter?

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.

what does this below rebus represent identXQQQQQME