Which of the following are sources of renewable energy? {Ans: Solar, hydropower, geothermal, wind, & biomass (sunlight, wind, rain, tides, geothermal heat).}What are the three main types of fossil fuels? {Ans: Oil, natural gas, coal}How long does it take to recharge water in Oahu's aquifer? {Ans: 25 years}Which of the following are concerns for the use of geothermal energy? {Ans: Scarcity of suitable sites, depleted if used too rapidly, some CO2 emissions, moderate to high local air pollution, noise & odor.}Why are invasive species successful in new environments? {Ans: Isolation leaves "open niches", lack of predators. Opportunities for invasion: are ocean, wind, bird migration, human introduction. Examples of invasive species: brown tree snakes, erthrina gall wasp, coqui frog,}Waste water treated to a level suitable for non-drinking purposes is called: {Ans: Recycled water.}