Please choose the correct answer to the question: Which factor best explains how many diseases, such as cancer, are formed within the body?

Answer1: A traumatic injury to the body has occurred. Answer2: A disruption in the cell cycle has taken place. Answer3: A response by the immune system was triggered by an allergic reaction. Answer4: A mutation occurred during the process of crossing over.

Answer format: answer1/answer2/answer3/answer4