The answer is D. Sentence 7. When it says "plates may also collide", it is bringing up another topic about the plates. As you read past sentence 7, you notice a shift in topic as you are reading. Instead of plates sliding against each other, the speaker is now talking about them colliding.
A. Sir Marhaus was killed and Sir Tristram was seriously wounded. In order to free his uncle King Mark of Cornwall, Tristan fought Sir Marhaus in a duel. Tristan was 18 whereas Marhaus was much older at the time of the duel. The faster Tristan won the duel but was wounded by Marhaus who used a poisoned spear during the fight and went to Ireland to be healed.
Answer:
B. They often are about people who lead relatively ordinary lives and have not done anything famous.
Explanation:
Some modern biographies and autobiographies are different from classic biographies and autobiographies in terms of content because they often are about people who lead relatively ordinary lives and have not done anything famous.
This is because, classic biographies and autobiographies were usually done for important people so that ordinary people could read about their life. However, in recent times, autobiographies and biographies can be done for the common man.