An example can be hot dogs and hot dog buns. If the price of one of them falls, it would lead to the product being cheaper which would increase sales, thus bringing the demand for the other one to be much higher.
Martin luther king jr, native american tribes & etc
Which word is italicized ? i dont see it here
Well the first thing to do is answer it if its important or just let it ring
Would you like to give me options? As soon as you do, I will edit my answer.