Wow, what a question. First, let me tell you a little bit about your eye. Your eye is like a camera. There is a lens (that's over the colored part of your eye). Behind your "lens" there are light detectors. They are very complicated and scientists still spend a lot of time trying to understand them. But we know that the light detectors pick up different colors. Some detectors only see green, some only see blue, and some only see red. If you were born with all of your light detectors being "red" detectors, then you wouldn't be able to see blue or green. Pretty weird, right? Well, some people do not have many red and green detectors and so they cannot see these colors really well.

Now that I told you about these light detectors, can you tell me what they are called? They have a special name that rhymes with "phone." If you find out, I'd love to hear back from you!