15. what are three methods or types of evidence used by scientists to determine when things happened?

Color blindness is a recessive trait. the gene for color blindness is on the x chromosome. the family tree below shows the trait of color blindness. the only unknown is the mother in the first generation

Are the earth's ocean floor and continents the same age geologically? why or why not?

Which description provides the best objective summary of the article in the passage?