If a woman is heterozygous for widow's peak (widow's peak is dominant over a smooth hairline) has children with a man with a smooth hairline, what
are the possible phenotypes of their children?
It is impossible to determine the possible phenotypes.
O All of their children will have a widow's peak.
O None of their children will have a widow's peak.
It is possible for their children to either have widow's peak or a smooth hairline.

It is possible for their children to either have widow's peak or a smooth hairline.

Explanation:

Let's say that the widow's peak allele is W (dominant) and the smooth hairline is w (recessive).

A woman heterozygous for widow's peak is Ww. A man with a smooth hairline must have two copies of the smooth allele since it is a recessive trait, so he must be ww.

The cross is Ww x ww

                    W               w

    w            Ww            ww

    w           Ww           ww

There is a 50% chance that the children will have the genotype Ww, and therefore have a widow's peak. There is a 50% chance the children will be ww, and will therefore have a smooth hairline.

So, It is possible for their children to either have widow's peak or a smooth hairline.

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.