Please choose the correct answer to the question: Which of the following is an example of ecological succession?

Answer1: a group of horses slowly becomes extinct due to loss of habitat Answer2: a group of rats in a lab learn to navigate a maze Answer3: a soccer team trains for the championship Answer4: Trees, insects, and birds in a forest grew from wildfire-ravaged lands

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