Fill in the Blanks Sustainabillity-first ruleOnline version Practice vocabulary on one rule for planet sustainability by ioanna ziaka 1 renewable alternative inexhaustible replace dependence solar fossil principles hydro coal sustainability One of the four of for the planet is to reduce our on fuels , such as oil , and gas . To do this we must increase the use of sources of energy . These include power ( taking energy from the sun ) , wind power and power . We call these sources , which means that the planet can these resources quickly by natural processes and are , in theory at least , .