Please choose the correct answer to the question: A farmer wants to know if adding fertilizer to his field will make his crops healthier. Which activity should the farmer do first?

Answer1: Plant different crops in a nearby fertilized field. Answer2: Water the crops in the field before adding fertilizers. Answer3: Add many different fertilizers to the field at once. Answer4: Record the appearance of the crops before fertilizing.

Answer format: answer1/answer2/answer3/answer4