Eye color, Hair color, Blood types, and Other Traits

March 6, 2020: I wanted to know how X inactivation and inheritance of X-linked recessive diseases in females are linked. For example, how do female carriers of colour blindness have normal vision?
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February 13, 2020: How many blood types are there and what are they? Can new types develop over time?
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February 4, 2020: One of my friends has blond hair and blue eyes despite being mixed (mother, white blond hair and blue eyes; father African-American, black hair brown eyes). My biology teacher says this is impossible, since both of those traits are recessive; however his sister also has blue eyes (but not blonde hair). Can you explain the genetics that would cause this?
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December 13, 2019: One of my 23andMe reports says that people with my genetics most likely have brown or hazel eyes. However my eyes are blue, green, and grey. I know you should take their estimates with a grain of salt, but how is it possible I have a completely different color from the report?
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