The Soviet Union possessed both scarce and abundant water resources. Electrical waste contains hazardous but also valuable and scarce materials. Such schools are relatively scarce and often difficult for families to locate. Supporting life in a territory with scarce freshwater resources is extremely costly. Health care services are particularly scarce in rural areas. Polyandry is believed to be more likely in societies with scarce environmental resources. There are also ethical questions on how to allocate scarce resources. Gasoline rationing proved an even better way to allocate scarce rubber. It served as a substitute for the increasingly scarce and expensive whale oil. Green is fairly scarce but blue and white are the rarest. Syria is a semiarid country with scarce water resources. This includes domination of food sources and competition for increasingly scarce nesting hollows. In the batch era, computing power was extremely scarce and expensive. Games involving scarce resources and strategy. During interference competition, organisms interact directly by fighting for scarce resources.