6. The word "brittle" in line 17 is closest in meaning to (A) easily broken (B) roughly made (C) hairy (D) shiny

3. Why was there nothing written about the making of Renaissance glass fibers until the seventeenth century? (A) Glassmakers were unhappy with the quality of the fibers they could make. (B) Glassmakers did not want to reveal the methods they used. (C) Few people were interested in the Renaissance style of glass fibers. (D) Production methods had been well known for a long time.