Which of the following is an external cost associated with hydroelectric power? It produces greenhouse gas emissions.
It requires dams and other infrastructure to be built.
It is not available for every geographic location.
It may cause permanent changes to aquatic ecosystems.
It requires frequent and expensive maintenance work.

Which sentence is true about preconception care? a. women who are thinking about having a child should not worry about preconception care as it is unnecessary. b. preconception care is health care you receive after you get pregnant.c. it is aimed at finding and taking care of problems that could affect you or the baby during pregnancy and steps to reduce birth defects. d. it will involve taking medication and a strict diet and exercise plan.