You are invited in a party with some gifts. Only certain things have to bring through.
You can bring a poodle but you can’t bring a dog.
You can bring a stool but you can’t bring a chair.
You can bring a rabbit but you can’t bring a hare.
What are three examples of something you could bring?

Without it all the world is gray and dull for everyone.
It reflects rays of sun, and yet it does not.
It captures light, and yet it does not.
What is it ?