What is unusual about mitochondrial dna ?

The shape

Explanation:

Mitochondrial DNA is in a circular shape unlike other cell DNA that is shaped in X patterns

There's a much higher mutation rate in mitochondrial DNA than normal DNA...

A mutation is a change in DNA sequence c:

Hope I was able to help!~

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.

c. is the correct answer