A
B
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D
E
100

I speak without a mouth and hear without ears. I have no body, but I come alive with the wind. What am I?

An echo. 

100

You measure my life in hours, and I serve you by expiring. I'm quick when I'm thin and slow when I'm fat. The wind is my enemy. What am I?

A candle. 

100

Voiceless it cries,
Wingless flutters,
Toothless bites,
Mouthless mutters.

Wind. 

100

This thing all things devours;
Birds, beasts, trees, flowers;
Gnaws iron, bites steel;
Grinds hard stones to meal;
Slays king, ruins town,
And beats mountain down.  

Time. 

100

What has roots as nobody sees,
Is taller than trees,
Up, up it goes,
And yet never grows?

Mountains. 

200

I have keys but open no locks. I have space but no room. You can enter, but you can't go inside. What am I?

A keyboard. 

200

The more of this there is, the less you see. What is it?

Darkness. 

200

What comes once in a minute, twice in a moment, but never in a thousand years?

The letter "M".

200

What has to be broken before you can use it?

An egg. 

200

Alive without breath,
As cold as death;
Never thirsty, ever drinking,
All in mail never clinking.

Fish. 

300

Thirty white horses on a red hill,
First they champ,
Then they stamp,
Then they stand still.

Teeth. 

300

A box without hinges, key, or lid,
Yet golden treasure inside is hid.

Eggs.

300

What is so fragile that saying its name breaks it?

Silence. 

300

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, and I can drown. What am I?

Fire. 

300

What can travel around the world while staying in a corner?

A stamp.