when discussing the animal kingdom, each creature belongs to a species scale of generalists to specialists. specialist creatures like the koala bear can only survive on an extremely limited set of conditions: diet (eucalyptus), climate (warm), environment (trees). generalists, on the other hand (think mice), are able to survive just about anywhere. they canwithstand heat and cold, eat your organic breakfast cereal or seeds and berries in the wild. so, specialist species thrive only when conditions are perfect. they serve a very specific purpose within their particular ecosystem and are good at navigating it. however, should those conditions change—as a result of nature or, more commonly, an outside force—specialist species often become extinct. in contrast, mice can move from spot to spot on the globe, adapt to different cultures, diets and weather systems. and most importantly, they stay alive.

종속절의 주어가 사라질 경우는 주절의 주어와 같은 경우인데
discussing을 보면 주절의 주어가 each creature입니다. 그런데 discussing 하는게 each creature이 아닌데
이경우는 어떻게 생각하면 좋죠?