The most commons forms of colorblindness are genetic conditions, passed along the x-chromosome. People with an x-chromosome and a y-chromosome only need their one x to be defective to catch it. People with two x-chromosomes need both to be defective.
Most women have two x-chromosomes (XX), and most men have an x-chromosome and a y-chromosome (XY). That's why colorblindness is much more common in men than in women.
Starfish, or more accurately sea stars, fill a niche as predator and prey in marine ecosystems close to shore. With more than 18,000 species in the world, they range from the tropics to the Pacific Northwest and further north. They can grow larger than a foot across and can have as many as 40 arms. While sea stars are known for their ability to regrow lost arms, they have an unusual digestive system, too.
Galaxy, solar system, star, planet, moon
The color red can indicate a positive result
