※ 밑줄 친 부분에 들어갈 가장 적절한 것을 고르시오. [문 15～문 16] The mistletoe plant typically attaches itself to the oak tree and uses the moisture and food from the tree for its survival. Sometimes the mistletoe can get so large that it ends up killing its host. This kind of example is called a(n) _____________ relationship.