Oh. You are a real scholar. You observe the world including society, animals, plants, etc. I read this interesting blog again, I really love this sentence: There are few examples better to show how in some cases, symbiosis greys the definition of what a plant and animal is.
At first, I can't understand what "grey" means. I even thought it was a spelling mistake. Suddenly I realize "grey" is simiar to "blur", I love this word "grey" so much, it is really the beauty of English language.