Organism at the end of a food chain

is always a higher organism

Explanation:

lets take an example:

food chain consisting of zooplankton, small fish, big fish and man

as the order goes in the question ,the organism at the end of this food chain is man

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.