Children have, probably since the beginning of human kind, always needed something to entertain themselves with. There are accounts as far back as the biblical times of children playing with various forms of toys. Realizing the need for children to be entertained, many companies and brands of toys have popped into the market, particularly during the 19th and 20th centuries. The toys they produce can be placed in a large list of different categories.
Here is a partial list of toy brands and/or companies:
... chain produces a proton-motive force, pumping H+ ions across the membrane; this produces a concentration gradient which can be used to power ATP synthase. This pathway ...