Why is there a much larger number of grass than snakes or hawks?

The prey will always out number the predator. This keeps the food chain going.

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)