In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Some modern boats are made out of metal, but what is a material that modern and original boats have in common?, Context: Wood has been an important construction material since humans began building shelters, houses and boats. Nearly all boats were made out of wood until the late 19th century, and wood remains in common use today in boat construction. Elm in particular was used for this purpose as it resisted decay as long as it was kept wet (it also served for water pipe before the advent of more modern plumbing).
Elm