a statue being weathered by acid rain a glacier advancing and retreating tree leaves changing colors soil depth increasing
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A student wants to use photography to study a process that occurs during one year. Which of these actions would be best for the student to study?
Possibilities:
- a statue being weathered by acid rain
- a glacier advancing and retreating
- tree leaves changing colors
- soil depth increasing

tree leaves changing colors