Final answer:
In a forest, each tree is an organism. Together, all the trees make up a population. And all the plant and animal species in the forest comprise a community.
Step-by-step explanation:
In a forest, each tree is an organism. Together, all the trees make up a population. And finally, all the plant and animal species in the forest comprise a community. So, in the given analogy, if PART is to WHOLE, then TREE is to FOREST.