UVA and UVB are two types of ultraviolet rays from the sun. UVA rays have longer wavelengths and reach deeper
[840호]
Camouflage is nature’s magic trick. It can hide something in plain sight. Animals use it to hunt o
[839호]
Birds from the same species can sound different depending on where they live. That is because young
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A carbon footprint is a number representing the total amount of pollution produced by a person, prod
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A zeppelin is a huge airship that floats slowly in the sky. It looks like a long, shiny balloon with
[836호]
A black hole is a place in space where gravity is so strong that nothing can escape ? not even lig
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Imagine a jar full of red and blue candies. You can’t see inside, and can only pull out candies an
[834호]
The origin of chess can be traced back to sixth-century India with a game called Chaturanga. The pie
[833호]
Oil paint dries much more slowly than watercolor because it doesn’t dry through evaporation. Inste
[832호]
Prostheses are special tools that replace missing or weak body parts. They can be outside the body,
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