How is a spark from touching a doorknob the same as a bolt of lightning? A. They are both caused by sound waves.
B. They are both caused by too many protons in the air.
O c. They are both caused by too much humidity in the air.
D. They are both caused by the attraction of protons and electrons.

A)When you touch a doorknob, all the charge wants to leave you and go to the doorknob. You see a spark and get a shock as the electrons leave you.

b)

D. They are both caused by the attraction of protons and electrons.

Explanation:

I majored in Biology

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.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).