What does the narrow line of hate means

If someone is treading a fine line, they are acting carefully because they have to avoid making a serious mistake, especially in a situation where they have to deal with two opposing demands. so i would think this means to be in a situation were someone really hates you. (idk i hope i helped)

halibut, flounder, tuna, and trout are all fish. so your first answer is 1.) fish. and since fish is edible, your next answer would be 3). edible

to describe those fishes more thoroughly, some of those fishes live in fresh water, and some of the fishes live in salt water, and that is not a thing that they all have in common. the question is asking what is common with all of the fish, so answer choices 2). fresh water and 4). salt water are not right.

the answer is not