You are given two true-breeding groups of gerbils. the gerbils in the first group have black coat color and curly tails; the gerbils in the second group have yellow coat color and straight tails. when you produce an f1 generation, you see only gerbils with black coat color and curly tails. when you produce an f2 generation, you see some gerbils with black coat color (75%) and some gerbils with yellow coat color (25%). you also see that some of the gerbils have straight tails (25%) and others (75%) have curly tails. if the single alleles responsible for coat color and tail appearance sort independently, how many of the black gerbils in this generation are expected to have straight tails?