Question 6 in regard to the estuary conservation strategy involving the removal of contaminated substrate, which of these statements are true? select all that apply. a it is one of the least expensive strategies for conserving estuaries. b it disturbs the biotic factors of the estuary floor. c it reduces contamination of the water and substrate of the estuary. question 7 mangrove forests have characteristics that make them unique. which characteristics do not differentiate them from other estuaries? select all that apply. a fluctuating salinity b low primary productivity c fluctuating water temperatures question 8 which features are used to classify a species as invasive? select all that apply. a adapts easily to the habitat and reproduces rapidly b competes with native species for survival factors c not edible for humans question 9 what produces the structure of coral reefs? a calcium carbonate b coral polyps c sodium bicarbonate question 10 true or false? the water content surroundng a black smoker is high in hydrogen sulfide and iron. a true b false question 11 how is energy produced in the aphotic zone? a marine rain b photosynthesis c chemosynthesis