Answer:
The Laura tried to grow micro-organisms in culture broth medium in Petri-plates but the microbial growth was not observed even on the fourth day of culture which could be due to:
1. Laura could have not provided the correct broth medium maintaining the with pH and salt concentrations.
2. Microorganisms did not get optimal growth conditions.
3. The bacterial source could have died after the collection which could have lysed after their death and thus no longer visible.
Ground my dude! wanna know how I know! I checked the other answers on the other one :)
Assuming the white phenotype is recessive. white: gg
I think the gray mouse is Gg because the offspring were pretty equally distributed in terms of color. See the punnet square below.
g g
G| Gg Gg
g| gg gg
If the Gray phenotype is recessive, then gray: ww but only if white is Ww because its about 50% chance for both.