Task: Paraphrasing
Input (English): Question: Which type of relationship exists when a certain type of tree’s roots need a fungus present in order to grow normally? 
Answer: beneficial. 
Sentence: A(n) beneficial relationship exists when a certain type of tree’s roots need a fungus present in order to grow normally.
Output (English): Tree roots sometimes need a fungus present in order to grow normally. When a tree's roots need the fungus present, it is a beneficial relationship.