Final answer:
The ports of New York, Boston, and San Francisco share characteristics of strategic location, serving as break of bulk points and having multiple transportation options which fostered significant economic growth and development. They also played an essential role in global trade and defense.
Step-by-step explanation:
The ports of New York, Boston, and San Francisco have several characteristics in common. These cities have grown into major metropolises partly due to their strategic site locations, which favor trade and industry. They are all located where multiple modes of transport intersect, creating vital break of bulk points where cargo can be transferred between ship, truck, barge, or train. This ability to break bulk has historically attracted a workforce, leading to a rise in warehouses, manufacturing, and economic growth. Moreover, these ports were crucial in connecting goods from different regions of the world to markets across the United States.
Specifically, New York City outgrew its competitors due to its enhanced transportation options, including its port, the navigable Hudson River, and the Erie Canal, which connected it to the Great Lakes region. San Francisco's port offered military advantages as a peninsula and sheltered harbor site, with the ability to control access through the Golden Gate. Additionally, the development of comprehensive public rail transportation, as in the case of San Francisco, significantly influenced the growth of these cities.