My question is when leaves turn red, do chloroplasts turn red or is a new substance that is red generated? To look into this question, I picked up a green leaf and a red leaf of the same species and observed them using the Foldscope. Looking closely at the green leaf, I was able to tell that it consists of a number of tiny rectangle green elements, which I think are chloroplasts. However, taking a look at the picture of the red leaf, the shape of red elements constituting the leaf was different from that of chloroplasts. The shape looks more circular and the borders between elements are much vaguer. Thus, I concluded that chloroplasts decayed and were replaced by a new red substance.