I would say the last one. Yes, the coral reef in the south is being threaten but, it’s not the only one. Many other reefs are being threatened. Why? To find the problem to this reef you need to find the problems of other reefs and compare the data. Which ever the most problem cause you get rid of that first.
The type of rock that will be formed is METAMORPHIC ROCK.
Metamorphic rocks are pre-existing rocks that are formed as a result of physical or chemical alteration by mean of heat and pressure. The process transform the rock into a denser, more compact rock. Examples of metamorphic rocks are marble, gneiss and schist. Metamorphic rocks can be formed from already existing igneous or sedimentary rock. <span />
Igneous rocks are classified by particle size
The answer would be AUTOTROPHIC