Population growth is the change in the number of INDIVIDUALS in a population over time.
If I am not wrong, I believe the answer is Producers. The reason as to why I say that producers is the answer is because in every food chain, there needs to be a base. That base is what provides the starting energy that will later on move up in the food chain.
Introns because they are coding sequences.
Exons because they are non-coding sequences.
I don't get it it's kinda confusing