20 points

which of these forms as part of the life cycles of both low-mass and high-mass stars as a result of a star-forming nebula collapsing and spinning?

a) protostar
b) black hole
c) supernova
d) white dwarf

answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;

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.

i won't lie i don't know so go online and ask google thats what i do