Answer:
Countries trade with each other when, on their own, they do not have the resources, or capacity to satisfy their own needs and wants. By developing and exploiting their domestic scarce resources, countries can produce a surplus, and trade this for the resources they need.
Answer: 3.6 seconds
Explanation: Geologic time is a way of measuring time based on events in the history of the Earth. If we compress this into one year, a single geologic year equals 4.6 billion years because the planet was formed 4.6 billion years ago.
Columbus arrived in the New World in August 1492, 528 years ago.
If 4.6 billion years = 1 year in geologic time,
528 years = 528 X 
=3.6 seconds
<em>(I broke the year down into seconds by breaking it down into days, then hours, minutes and seconds because the value is very small)</em>
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<em>So, if we compress geologic time into a single year, only 3.6 seconds have elapsed since Columbus arrived in the New World</em>
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That is false, all muslims that can financially make the pilgrimage to the holy site of Mecca are required. The holy pilgrimage to Mecca, also called Hajj, is one of the 5 pillars of Islam.
The correct answer is - C. The river carried enormous amounts of silt.
The Yellow River, got this nickname because it is yellowish from the enormous amounts of silt it carries. When there were heavy rains, or the snow was melting, the river got more water, but also more silt, so the silt was partially blocking the free movement of all of the water, so it was flooding the surrounding are. In one way, the floods were terrible because they were destroying pretty much everything on their way, but on the other side, were living huge amounts of deposits that were fertilizing the soil for the agriculture.