Darker skin produces more what than lighter skin

Joe is breeding cockroaches in his dorm room. he finds that the average wing length in his population of cockroaches is 4 cm. he chooses the six cockroaches that have the largest wings; the average wing length among these selected cockroaches is 10 cm. joe interbreeds these selected cockroaches. from earlier studies, he knows that the narrow-sense heritability for wing length in his population of cockroaches is 0.6. a. calculate the selection differential and expected response to selection for wing length in these cockroaches. b. what should be the average wing length of the progeny of the selected cockroaches?

All individuals have two alleles for a given trait. according to mendel's these alleles are passed down one each from both mother and father.

How would you describe the the organisms in the second row of model 1 that are connected to the parents by a line