Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

What is the word or phrase?

Out of the nine cats that you can see in the picture, there are only two that are completely identical. Can you find them out?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

You Throw The Outside, Cook The Inside
Eat The Outside, Throw The Inside.

What Is It?

Can you place three balls such that the equation shown in the picture holds true?

I can be cracked, made, told, and played. What am I?