Over the past 500 million years, mass extinctions have occurred in which at least of the species on earth became extinct.

Color blindedness is a sex-linked trait. if we could see the pedigree chart for several more generations of the family illustrated here, we would expect a) more males to be color blind. eliminate b) more females to be color blind. c) no females to ever be color blind. d) an equal number of males and females that are color blind.