As long as you are referring to the green plants aka producers of the food chain/web.
Anton van Leeuwenhoek :-))
Answer:
D. geographic isolation.
Explanation:
As the Grand Canyon formed, it became a physical barrier to the mixing of squirrels from its northern and southern sides. Each squirrel population was confined to a single side. This type of separation is referred to as geographic isolation.
I have encountered this question before, and the given diagram shows no producers. Moreover, it consists of pictures of five organisms, with no relationship being shown between them. Therefore, in order to make the model more accurate, Maria should add B. The sun and arrows to show the flow of energy.