What does this rebus puzzle means ?

What is so fragile that saying its name breaks it?

What have one eye but still cannot see?

I am a word that begins with the letter “i.” If you add the letter “a” to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

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

What always comes into a house through the keyhole?

Who always enjoys poor health?

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be ?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?