I'm pretty sure that the answer is D!! Hope this helps you!!!
The Calhoun doctrine shows that Calhoun wanted states to have the right to nullify national laws
Answer: B) African countries were not invited nor welcomed to this meeting.
All of the 14 participants of the Berlin Conference were European, with the exception of the Ottoman Empire which, even thou it controlled some territories in northern Africa, they were autonomous territories.
Besides that fact, there was no participation by any African country, since the conference´s goal was to regulate European colonialism and trade throughout Africa.
Be careful what category you put your question into next time!
It is where the ozone layer is located and it protects from harmful gamma rays and the sun from making the Earth too hot
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