Answer:
Man's most important invention.
What instrument can make any sound and be heard but not touched or seen?
What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?
Where is the ocean deepest?
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?
What is lighter than what it is made of?
Easy
Animal
Difficult
Food
Funny
Kids
Logic
What am I?