Essential in protecting the mainland from heavy wave activity, due to their deeply embedded roots.
select one:
a. shrubs
b. coral reefs
c. mangroves
d. palm trees

It's C. Mangroves. This is true because The roots of mangroves help absorb the action from waves and help prevent shoreline erosion. When these trees and shrubs are removed, additional support structures such as seawalls are needed. Along the same lines, seagrass stabilize sediments on the seafloor.There are 80 described species of mangroves, 60 of which live exclusively on coasts between the high- and low-tide lines. Mangroves once covered three-quarters of the world's tropical coastlines, with Southeast Asia hosting the greatest diversity. Only 12 species live in the Americas. Mangroves range in size from small bushes to the 60-meter giants found in Ecuador. Within a given mangrove forest, different species occupy distinct niches. Those that can handle tidal soakings grow in the open sea, in sheltered bays, and on fringe islands. Trees adapted to drier, saltier soil can be found farther from the shoreline. Some mangroves flourish along riverbanks far inland, as long as the freshwater current is met by ocean tides. Hope this helps!

Its decreasing because of illnesses