Question 45-48 are based on the following passage. 

    For many years, scientists have recognized a number of symbiotic relationships that develop between human and animal species. Typically, these relationships have been categorized as mutualistic, parasitic, or commensal in the cases of wild animals, and domestication in the cases of livestock and companion animals. Recent studies, however, suggest that there should perhaps be another category to describe those creatures that seem able to set e within human societies, benefiting from certain human behaviors while nonetheless tamaining wild.

    In order to more fully comprehend this phenomenon, commonly referred to as synanthropy, a new breed of scientists has developed. Traditionally, the fields considered most prestigious and thus most likely to draw financial support have been those centering on exotic and endangered animals, or those animals actively used as labor, companionship, or food stock by humans.

    Species that can be characterized as having a synanthropic relationship with humans, however, fall into neither category, as they tend to be both common and local. Ironically, it is those very species with which humans must interact on a daily basis. So perhaps it is fortuitous that, at long last curious individuals have begun to study those species on a more serious basis. Urban wildlife, such as rats and pigeons, may not draw the admiring looks that a cassowary or koala do, but most people living in metropolitan areas will interact with the former on a regular basis while never seeing the letter outside of a zoo. 

According to the passage the word "synanthropy" I could best be defined as ....