Question

5. He is my … brother, but he is not as smart as I am.

a) older
b) elder
c) the older
d) the elder

6. This month I've read two books: The Lord of the Flies and Brave New World. I liked … much more.

a) the latter
b) the latest
c) the later
d) the late

Answer 1

5. a) older - просто как прилагательное
6. a) the latter - Пояснение: 

Use latter to refer to the second of two persons or things that have been mentioned. When more than two have been mentioned, use last.
For example:
He preferred oranges to apples, because the latter were not as juicy.
He saw Leathal Weapon 1, 2, and 3 and liked the last one most.