Which of the following statements about resource use is true? a. the use of renewable resources has no inherent costs. b. resource use, whether renewable or nonrenewable, must be carefully managed to reduce the impact on the environment. c. nonrenewable resources are used for energy, because there are no renewable resources that can be used as a source of energy. d. the overuse of nonrenewable resources is less environmentally damaging than the overuse of renewable resources.