The answer is public services. Hope this helps!
According to the article, jellyfish are invading the oceans near JAPAN. Fisherman in the area assert that the amount of fish and jellyfish in the waters have shifted drastically during their lifetime. There is a large abundance of jellyfish (making it difficult or impossible to fish some days) and a small number of other kinds of fish.
Humans may have caused this problem by over-fishing disrupting the balance of the underwater ecosystem. Jellyfish are eaten by some fish and compete with other species of fish. Also humans building docks, bridges, and other water infrastructures have led to a decline in habitat availability for jellyfish.
Earth's rotation causes air and water in the northern hemisphere to appear to move right and in the southern hemisphere to appear to move left
Endemic diseases result in a decreasing population, so with that said you can rule out choices B and D.
Among the two left, letter A is the most appropriate answer. Not all endemic diseases have an effect on the number of children a population will have. So if we are speaking about endemic diseases in general, the answer is:
A. Endemic diseases can result in decreasing population numbers: many people die form diseases, and others move away from or avoid moving to places where diseases are rampant.