11. does water have a high or low surface tension? 12. what does all the water on earth make up? 13. what is salinity? 14. does fresh water have a high or low salinity? 15. what is a river basin? what river basin is clinton, nc located in? 16. what is an estuary? 17. how do estuaries protect pollutants from entering the ocean? 18. how are estuaries affected by hurricanes? 19. why are estuaries good nurseries for marine organism? 20. where does an organism live if it is a marine organism?