1- in a species of mice, brown fur color is dominant to white fur color. when a brown mouse is crossed with a white mouse all of their offspring have brown fur. why did none of the offspring have white fur?

The offspring did not have white fur due to the fact that white fur is a recessive trait. One parent had brown fur, which is a dominant trait, that cancels out the recessive trait and that is why the offspring did not have white fur.

Since a female is both xx chromosome and the male passes down the x chromosome, than the offspring would be female since a female is xx.

Mg is used to measure mass