4. Identifying Cause and Effect- Explain two reasons thatthe American Colonization Society failed to end slavery in
the United States.
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i am not to sure if this is correct but i think it is because

so many people used their money to buy slaves and they were not ready to give it up, also most did not think of themselves at the same state as a black person. even after the slavery ended many people did not except black people in their lives.

Explanation:

the answer is b for brother

a. poison gas was sprayed over battlefields by airplanes to weaken enemy positions before major attacks.