Why was it so expensive to buy a book before Gutenberg invented movable type?

Ineed on 2-4 i want y’all to reply to this question so i can turn this into my teacher tomorrow

Why are slanted roofs found on many buildings within russia and finland? a. to prevent ice slides. b. to prevent the build-up of water during heavy rains. c. to prevent heat from escaping during the clod winter months. d. to prevent snow build-up.

Match each mode of narration to the excerpt in which it is used