I believe the answer is A. natural harbors provided a place to safely dock ships.
You ask a question that you don't regarding school subjects and others who come across your question and know how to answer will help you and reply
Answer: to preserve the past
cite: The goal of a command economy is for governments - not private enterprises - to manage country economies. In a command economy (also known as a planned economy), government central planners determine what goods and services will be produced, the amount of goods and services produced, and at what cost to the consumer.
They used triangular sails that allowed these ships to travel better.
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William Clark
Lewis and Clark remember???