You are looking at the color of feathers in ducks and find that Green feathers (G) are dominant to yellow feathers (g). However, a second gene, H, controls whether the color will be expressed in the feathers. If the duck is hh, the duck will always be white, because the pigment does not go into feathers. What ratio of phenotypes in the progeny would you expect following a dihybrid cross

Option C , 9:3:4

Explanation:

The options for the questions are there in the attachment

Solution-

This is the case of recessive epistasis in which recessive allele has a masking effect on  alleles G and g.

GgHh * GgHh

The offspring will be

GHGhgHgh

GHGGHHGGHhGgHHGgHh

GhGGHhGGhh GgHhGghh

gHGgHHGgHhggHHggHh

ghGgHhGghh ggHhgghh

Green colored - 9

Yellow colored - 3

White colored- 4

chert is a sedimentary rock composed of microcrystalline or cryptocrystalline silica. with this little bit of information, you can come to the conclusion that your answer is c.  

explanation:

the answer to your question is tooth decay.