Please choose the correct answer to the question: A scientist was examining a large boulder that was covered with lichens (a combination of fungi and algae). He chipped a piece of the rock and placed it under a microscope. He observed that the surface of the rock was breaking down underneath the lichen. Which was the scientist most likely observing?

Answer1: the interaction between abiotic factors Answer2: the effects of chemical weathering Answer3: the process of deposition Answer4: the effects of abrasion

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