Please choose the correct answer to the question: Noah visited a park that had many oak trees. Which best describes the role of an oak tree in its ecosystem?

Answer1: Oak trees can live for a long time. Answer2: Oak trees have leaves that change colors. Answer3: Oak trees have strong branches and trunks. Answer4: Oak trees are a source of food and shelter for animals.

Answer format: answer1/answer2/answer3/answer4
Answer: answer4