Which compound is composed of oppositely charged ions?

The functioning of an electron transport chain is analogous to a) a slinky toy going down a flight of stairs. b) a canoe going over a waterfall. c) a person climbing a flight of stairs one step at a time. d) a person leaping from the top to the bottom of a flight of stairs in one jump.

How have the competing explanations' experiments on atoms affected the development of the atomic model?

What is relative velocity? in which condition is relative velocity known by adding the velocity of the first body and that of the second body