A lone male wolf, who doesn't have a pack, travels the forest. When he reaches a new hill that he hasn't been on before, he spends a large amount of time sniffing the trees and rock outcrops. Finally, he turns and heads back from where he came, recognizing this is the territory of another wolf. What's most likely responsible for communicating this information to the wolf?

The correct answer is pheromones.

Explanation:

The chemical substances, which are produced and discharged by various kinds of animals into their surroundings, to mark their territory and affecting the behavior of the individuals of the same species are termed as pheromones.  

The animals like wolves use the chemical messages known as pheromones by applying their sense of smell. The pheromones or the chemical messages are used for communication between various individuals of similar species.  

the endomembrane system is a series of compartments that work together to package, label, and ship proteins and molecules. in your cells, the endomembrane system is made up of both the endoplasmic reticulum and the golgi apparatus. these compartments are folds of membranes that form tubes and sacs in your cells.