Which is true of a step-down transformer but not a step-up transformer? The core is made of copper and the coils are made of iron. The primary winding has fewer coils than the secondary winding. The primary winding has more coils than the secondary winding.
The child only comes out as homozygous dominant (YY) for the trait in 1/4 boxes in the Punnett Square. This translates to the child having a 25% chance of being homozygous dominant for the trait.