2. How can dominance and expression of alleles explain the differences between these fraternal twins?

Fraternal twins are from two seperate eggs.

Explanation:

The first part of the question is missing but any difference between fraternal twins can be explained by the fact that two seperate eggs are fertilized during the pregnancy so they have different genomes which leads to having different dominance of different genes and this leads to different expressions of this genes.

I hope this answer helps.