Due to global warming, the climatic conditions such as rise in temperature of the coral habitat in the oceans changes. The corals become stressed by changes in conditions. Under these conditions, corals expel the symbiotic algae living in their tissues. This turns corals completely white. This is called coral bleaching. Due to coral bleaching, it becomes more stressed and this can leads to its death. Algae also may not be able to survive alone.
Density is mass of object per unit volume
The reason as for why the atmosphere exerts a force or pressure, force over a given area, is because of the particles of Gases within the air, oxygen, carbon dioxide, nitrogen etc, all constitutes air, and the weight of air is ultimately what exerts pressure.
The solution is A. Because of the weight of air.
