A coastal area that once supported a thriving fishing industry is overfished. The number of species found living in the marine ecosystem continues to decrease. Which of these activities is most likely to increase the natural biodiversity in the area

The answer is "Building artificial reefs and limiting fishing activity".

Explanation:

A variety of different methods could be used to construct an artificial island, which is most habitats are built to create a coral through using raw parts, and farming is the farming company, both "the creation of artificial reefs and restriction of fisheries" the activities are used to control environmental ecosystems throughout the region.

b. the carbon cycle ensures living things have a source of hydrogen

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.