Question

read the passage.
despite hippopotamuses being relatively slow - moving mammals, they are quick to display their territoriality. when hippos sense a potential intruder encroaching upon their watery habitat, they respond aggressively. armed with powerful jaws and sharp canine and incisor teeth, they are often regarded as one of africas most dangerous animals when threatened. for the most part, they appear to be more highly reactive in the water than when they venture onto nearby land. in some cases, hippos have been known to overturn whole boats while defending their home range.
what is the meaning of encroaching as used in the passage?
advancing past established boundaries
returning home to ones place of origin
existing within a complex ecosystem
observing an area from a distance

Explanation:

The passage describes hippos' territorial behavior. When an "intruder" is "encroaching" on their habitat, they react aggressively. The context of territoriality and defense implies that "encroaching" relates to entering or advancing into their space (boundaries). The other options: "returning home" (opposite as it's an intruder), "existing in ecosystem" (not about entering a specific territory), "observing from distance" (no indication of just observing, they react to the intrusion) don't fit the context of territorial defense.

Answer:

advancing past established boundaries