I believe the answer is (B)
<span>a complex series of feeding relationships with many organisms interacting and depending on each other </span>
<span>The correct answer is B. Pulmonary. The answers C. Cerebral and D. Extremity, are baseless regarding this question; A. Systemic could be a good alternative, as the blood flows from the systemic to the pulmonary circulation in the right side of the heart; but the systemic circulation is in fact mostly handled in the left side of the heart, while the right side handles the pulmonary one. </span>
The reason they have to be so accurate and precise is because, let's say you were doing a lab or something that was involving chemicals. If you had to put a certain amount of chemicals in your experiment, but when you were doing to the math, you messed up and didn't go back and even bother to fix it, that is a really BIG issue. Because something will probably happen to your chemicals because you might have added to much of something into it. So that's why you always have to be so precise and accurate!
Ocean waters has its own level of density which depends of the climate, temperature and most of all the location where it came from. The more the ocean water absorbs heat the more its density as a result it rises above from cold to hot. So the the water from the Antarctica usually is less dense and then become more dense when it goes to the equator which is more hot.
