Afuel cell combines hydrogen and oxygen to produce electricity, heat, and water. fuel cells are often compared to batteries. both convert the energy produced by a chemical reaction into usable electric power. however, the fuel cell will produce electricity as long as fuel (hydrogen) is supplied, never losing its charge. nasa uses hydrogen fuel to launch the space shuttles. fuel cells are a promising technology for use as a source of heat and electricity for buildings. where else are hydrogen fuel cells used? all, but one, apply.

answer:

hydrogen and fuel cells can be used in a broad range of applications. these range from powering buildings, cars, trucks, to portable electronic devices and backup power systems

explanation:

the arab empire adopted the muslim religion as their main belief. arabs would influence the people from the territories they invaded towards islam (the muslim belief).

nevertheless, throughout the history of the arab empire, rulers brought intellectual individuals from other religions to their centers of learning. these other foreigners included jews, christians, greeks, persians, and indians.   these resulted in the adoption of important knowledge developed by these cultures by the arabic empire. for example, the works of aristotle were translated from greek to arab and indian scientists brought the numerical concept of "zero" to the arabs.

nowadays, 93% of the arab population is muslim, which at the same time is subdivided in sects including the sunni, zaini, alawi, shia. the remaining 7% is composed mainly of christians.

c. reserves power to the states and people