The correct options are B AND D.
Agriculture was the major means of survival for men during the early days. Fluctuations in the rainfall during the course of a year may adversely affect the crops grown. If this persists for a long time it will leads to food shortage and famine.
Earthquake and eruption volcanoes are shift in the physical environment which can easily destroy any community.
Basically, a citizen of the United States is any person who is in possession of the citizenship, which can be acquired by being born on the territory of the US or by being naturalized. The citizens, unlike other legal residents, can choose their representatives in elections.
The Tulsa race riot of 1921. It happened between may 31 and june 1.
