You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Copper

Context:
Copper compounds in liquid form are used as a wood preservative, particularly in treating original portion of structures during restoration of damage due to dry rot. Together with zinc, copper wires may be placed over non-conductive roofing materials to discourage the growth of moss.[citation needed] Textile fibers use copper to create antimicrobial protective fabrics, as do ceramic glazes, stained glass and musical instruments. Electroplating commonly uses copper as a base for other metals such as nickel.

Question:
What does copper wires along with zinc on roofs help to prevent?

moss