In griffins, the allele for black feathers (B) is dominant over silver feathers (b) which are recessive. Two black griffins are crossed and have a silver offspring. What is the genotype of the parents?

The correct answer is - Bb and Bb.

Explanation:

In this case, there are two traits decided by the black "B" allele that is dominant over "b" which is silver. In this case the cross between two black feather birds and the there would be genotype:

BB and BB or Bb and Bb or Bb and BB

1.  In first case, and the third case, there is no or only one allele for the silver trait so the correct answer would be - Bb and Bb

    B      b

B  Bb     Bb

b   Bb    bb

thus, the correct answer is - bb which is silver feather.

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)