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

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

Find the value of "?" in the ball picture Riddle below:

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Replace the question mark in the picture below.

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

During an experiment, a guy throws a bouncy ball from a 100 feet tall building. The ball has a specific characteristic. Every time it hits the ground, it bounces up halfway.

How many bounces do you think the ball will make before it comes to a stop ?

What is wrong in the below Picture?