What does the nosepiece do on a microscope

The nosepiece rotates to easily change the magnification. It holds two or more objective lenses that hold different degrees of augmentation power. This allows the person using the microscope to locate and detect different objects using a lower power lens and then examine the objects more closely with the high power one. There would only be one level of magnification if it didn't have a nosepeice .

not the best question format lol but what i think might as scale color is controlled by a single gene with two alleles, the green allele and the yellow allele. when moths that are homozygous for green scales are mated with moths that are homozygous for yellow scales, 100% of the offspring have green scales.