Tại sao ở vùng cửa sông đổ ra biển luôn có sự bồi đắp phù sa?

How are the freedom of religion and the freedom of assembly alike? both involve the freedom to express oneself. both were an original part of the constitution. both were practiced by the early puritans. both were denied to immigrants.

Why would the rumor of a government contract change the value of this companys stock

Why would the free rider problem prevent a private business from investing in the building of a city sidewalk?