The answer is artificial reef. Its a man made underwater structure typically built to promote marine life areas with a generally features bottom to control erosion, block ship passage or improve surfing. Artificial reef improve marine life in a certain area and deprive a new location for fishermen to fish and which works to ease the pressure on natural reefs.
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The correct answer is A. silica.
The amount of silica found in the magma determines the viscosity. The higher the silica in magma, the higher the viscosity of a magma. So the correct answer is silica. It is not among the other choices.
A lot of people want geologists, local councils are always in need of a geologist so that is an easy career. A geologist is a good career because people are looking for them and they become more and more important. I hope that helps
D. They are not known for high birth rates
Because it is surrounded by land that is a lot flatter