Perception is the abiltity to become aware of something through your senses. Vision is what allows you to see things.
Here, Hamlet is using a metaphor. Metaphors compare two things, yet differ from similes in that they don't use "like" or "as." He is comparing Denmark to a prison, meaning that he feels that the city is confining and bleak.
The class of '09 held its graduation ceremony at 7 o'clock
I guess it would be easier for us to define the disadvanatges if you tell us about the technologies you want to mention. For example, it is hard to think of technology and nature together but even advances like Artificial Intelligence (AI) that could not be further removed from the natural world are helping conservation efforts. Well, at least I tried to answer your question. More help you can get if you check the tips at Prime Writings site. Good luck with it!