A population of ducks lives in an area that floods many times each year. Some of the ducks are better at finding food on dry land, while other ducks are better at finding food in wet, muddy areas. Eventually, the land around the lake permanently changes from dry soil to wet, marshy mud. How will this change to the land most likely affect the duck population?

The population will remain stable because the ducks will not be affected by this kind of change.
The population will eventually balance out so that there are equal numbers of both types of ducks.
The population will evolve so that most ducks survive no matter how they find food.
The population will evolve so that most ducks are better at finding food in wet, muddy areas.

D. A duck flies to another pond.

The above sentence is an example of emigration. Emigration refers to moving from one area to another for a long or permanent period. In this instance, a duck is leaving the pond it originally resided in (along a population other ducks) in order to reside in another pond. Therefore, it can be said that the duck "emigrated".

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.