What did the Europeans have to do at the end of each trading season?​

To sell all the goods and buy necessary items.

Explanation:

The Europeans have to sell all the goods and buy the necessary materials that is needed in the family as well as for the next trading season at the end of each trading season. The ending of trading season provides resting time for the traders to collect and produce new products for the coming new season. This period of time the traders spend their time in their houses with family and producing new items so that they can sold it in the coming trading seaason.

the dust bowl, otherwise known as the dirty thirties, was a huge dust storm that killed multiple (and i mean  multiple) farmer's crops, leaving them homeless, and foodless, and jobless. in california, there were 5.7 million residents, and the population shrank as mexicans were repatriated. however, when the dustbowl happened, a lot of people began to move to california. by 1940, 250,000 people had arrived. therefore, your answer would be  the population increased, massively.  i hope this !

explanation:

the second significant cause of the great migration was the desire of black southerners to escape segregation, known euphemistically as jim crow. rural african american southerners believed that segregation - and racism and prejudice against blacks - was significantly less intense in the north.