HELP HELP What is it called when organisms that were once the same species no longer interbreeds/mates?

Natalie’s white rabbit had a litter of six bunnies. four bunnies were black and two bunnies were white. the father of the bunnies is black. natalie wondered why there were more black bunnies than white bunnies in the litter. a. all of the black bunnies are male and the white bunnies are female. b. the fur color has nothing to do with the parents. it depends on the environment. c. the bunnies got more traits for fur color from their father than from their mother. d. there are fewer white bunnies because they do not survive as well as black bunnies. e. there are more black bunnies because father rabbits have stronger traits for fur color than mother rabbits. f. each parent contributed the same amount of information about fur color during reproduction. g. there must have been something wrong because black rabbits and white rabbits should produce grey rabbits.