Reading Text
Most human beings are "trichromats." This means our eyes have three types of cone cells that help us see colors: red, green, and blue. With these three cones, the average person can see around one million different shades of color.
However, a small percentage of women have a rare genetic condition called tetrachromacy. These women are born with four distinct types of cone cells in their eyes instead of three. Because of this extra cone, a tetrachromat can see subtle variations in color that look completely identical to anyone else. Scientists estimate that a person with tetrachromacy can see up to 100 million different colors! Many women with this condition do not even realize they have it until they take specialized color tests.
1. Key Vocabulary
- condition (noun): An unusual physical state or medical situation.
- distinct (adjective): Clearly different or separate from other things.
- subtle (adjective): Small, delicate, and difficult to notice unless you look closely.
- identical (adjective): Exactly the same in every way.
- estimate (verb): To guess or calculate the cost, size, or value of something roughly.
2. Reading Comprehension Questions
- How many types of cone cells does an average person have in their eyes?
- Who is usually affected by tetrachromacy?
- How many colors can a person with tetrachromacy see?
3. Grammar & Tenses Focus: Modal Verbs (Can, Could, Might)
Fill in the blanks with can, could, or might based on the context.
- Average humans ________ see about one million colors.
- A person with tetrachromacy ________ notice tiny changes in color that you cannot see.
- In the past, scientists ________ not explain why some people saw colors differently before they studied cone cells.
- If you take a color test today, you ________ discover that you have an extra cone cell!
