I believe the answer is "biodegradable". Hope this helps!
Blood vessels visible in the posterior view of the heart include the Superior and inferior vena cava and the pulmonary veins. The superior vena cava and the inferior vena cava drain systemic venous blood into the posterior wall of the right atrium. The pulmonary veins transport blood from the lungs back to the heart and are best seen in posterior view of the heart. Other features visible in the posterior view include, right and left atrium, right and left ventricle, aorta, aortic arch, pulmonary veins and arteries, coronary sinus, coronary artery and posterior interventricular artery.
C. Is your answer. Electrons are negatively charged.
