"IF you use any key phrasing from a source – if you quote directly at all – you must indicate that you are doing so"
this is the question I'm dealing with, I need to know in simple terms what is key phrasing? it is another form of paraphrasing? I look it up on google but I honestly don't understand

This is the mountain range known as the alps. which of these statements regarding the alps is true? a) the alps are the largest mountain range in asia. b) the alps protect the roman empire from invasion. c) the alps were key in preventing england from being conquered in warfare. d) the alps prevented the roman empire from taking control of most of europe.