Answer:
8/16 or 1/2
Step-by-step explanation:
This question is a dihybrid cross involving two genes, one coding for feather color and the other for beak length. The alleles for green feathers (G) and long beak (L) are dominant over the alleles for yellow feathers (g) and short beak (l).
According to this question, a male with genotype GGLl was crossed with a female with genotype Ggll. The following combination of gametes is produced by each parent:
GGLl - GL, Gl, GL, and Gl
Ggll - Gl, Gl, gl and gl
Using these gametes in a punnet square (see attached image), the following offsprings in the following proportions will be produced.
Green feathers, long beak (GGLl, GgLl) = 8/16 or 1/2
Green feathers, short beak (GGll, Ggll) = 8/16 or 1/2
Hence, the probability of short beaks (ll) in the offspring of the cross is 1/2.