After 3 hours of exercise, what are the main sources of energy?

After three hours of exercise, the main sources of energy are the following;

·         Plasma free fatty acids – this is used as an energy in which they provide in every organs in the body of a living organism.

·         Blood glucose – The glucose can provide energy in the body in which they are found in the sugar of the blood.

answer: 2

explanation:

yes

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.