What might be the correlation between the clarity of the lake water and the occurrence of the full body plate trait? What might you conclude about the clarity of the water from 1950 to 1980 based on this correlation?

The clarity of the lake water isn’t specified so assuming the clarity improved and other predatorial fish were able to target stickleback fish more easily the full body plating had to come into play to make it more difficult for them to be preyed upon and to give them a better chance at escape.

Explanation:

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.