The type of sentence given is a compound sentence. It is a compound sentence because it consists of two independent sentences: "I already said yes to someone else" and "I can't go to the dance with you". In order to link the two sentences, the conjunction "because" is used.
There are several situations where a minority group stood up against the dominant group. One of the more famous examples is the Black Lives Matter movement. It is an international activist movement that advocates the protection of African-American against oppression and discrimination.
7-10 sentences depending on the length.
Answer is authority
p.s. I took the test / quiz