Starting in the late 1300s, russian princes fought to drive out of russia. -the vikings -the serfs -the slavs -the mongols i think it is either vikings or the serfs what do you say?

Which are practical examples of how people in the developed world could make a big difference in how much water they use check all that apply a. use lightbulbs that use less electricity b. consider using a composting toilet that does not use water c. avoid using your telephone during peak hours d. do not read books