Answer:
Bull = Pp
Cow A = pp
Cow B = pp
Cow C = Pp
Explanation:
In cows polled (P) is dominant over horned (p) trait.
The bull is polled so it can be PP or Pp. Cow B is horned so it must be pp. Resultant offspring from bull X Cow B is also a horned calf (pp). This calf must have received one p from the bull. So the bull's genotype is Pp.
Cow A is also a horned cow so it must be pp. When bull X Cow A, a polled calf is produced. Since the bull's genotype is Pp and Cow A's genotype is pp, this polled calf will be Pp like the bull.
Cow C is polled like the bull so it can be PP or Pp. However on crossing with the bull (Pp) a horned calf is produced (pp). This calf got one p allele from the bull and p allele from the Cow C. So Cow C's genotype must be Pp.
Hence,
Bull = Pp
Cow A = pp
Cow B = pp
Cow C = Pp
Magnification = 40mm/ 40 micrometer = 10^3
Answer: 0.1%
Explanation: I remember taking the test and it should be 0.1%, because it go's through all the other animals and last, the hawk.