Final answer:
The term for two prokaryotic populations interacting where one benefits and the other is unaffected is commensalism. One example would be birds that feed on insects disturbed by grazing animals without affecting the animals.
Step-by-step explanation:
When considering the interaction between species, specifically when a field mouse is seen running across the ground searching for food, this is an example of foraging behavior rather than a symbiotic relationship such as mutualism, commensalism, parasitism, or predation. However, if we refer to the interaction between two prokaryotic populations where one benefits and the other is not affected, the correct term is commensalism. This would be similar to certain types of insects that catch free rides on larger insects or birds that feed on insects stirred up by larger grazing animals without affecting those animals.
On the other hand, species that benefit mutually from their relationship are involved in a mutualistic relationship. An example of this is the relationship between Karner blue butterfly larvae and ants, where the larvae provide carbohydrates to the ants, and in return, the ants protect and tend to the larvae.