Blue-eyed mice interbreed and produce progeny with a 2: 1 ratio of blue to non-blue. when blue is crossed with nonblue, a 1: 1 ratio of the two classes is obtained. non-blues interbreeed to produce all non-blue offspring. explain these observations. support your explanation with details about phenotypes and genotypes.

Explanation:

The results are explained if the trait blue eyes is dominant (B) over non-blue (b) and the dominant allele B is lethal in homozygous individuals.

The possible genotypes and phenotypes are:

When blue (Bb) is crossed with non-blue (bb) the resulting offspring is 1/2 blue (Bb) and 1/2 non-blue (bb).

When non-blues interbreed (bb X bb) all progeny is non-blue (bb).

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.