Sand and gravel are important marine resources. they are used to make concrete and for other industrial purposes. as a marine biologist, what information would you need to evaluate the impact of mining these resources? a. how much was being mined, and how the activity would impact the water temperature b. how ecologically sensitive the area is, and how the activity would impact the benthic organisms c. what products are made with the resources, and how the activity would impact the ph of the water d. what commercial value the resources had, and how the activity would impact the offshore currents