Threateningly
We can tell that because the dogs are huddled together in fear, there's some sort of danger. Also the snarling suggests they are under caution or going on defense from some danger; they feel threatened.
Answer:
Progressive implies something that is happening in stages, while Advanced implies that the stage has moved forward to a large extent.
Explanation:
Progressive and advanced are both adjectives used to describe the stages of an event or activity. Progressive implies continuity or the ongoing state of the activity. It also connotes the idea of something that is meeting up to current trends. For example, the old Professor has progressive knowledge of Information Technology. Advanced refers to the fact that the activity has progressed to a far stage.
Progressive: The ailment is progressive.
Advanced: The ailment is advanced.