Answer:
b) It started as a fringing reef
Explanation:
When an island (basically a seamount or eroded volcano) that is formed on a caldera and which is surrounded by fringing reefs starts to sink or the sea level starts to rise gradually and engulf it , i.e. when the fringing reefs starts to grow it gradually forms an atoll .
It is basically a coral reef encircling a logoon . Coral starts to grow and build a fringing reef and later this barrier reef forms the atoll , which encircles a lagoon .
The answer is : Tectonic plates
This scarcity may be due to bad quality of water. Lately, there has been a growing concern that even if there is ample water to meet the needs of people, much of it may be polluted by domestic and industrial wastes, chemicals,pesticides and fertilisers used in agriculture making it hazardous for human use.
Due to Saturn's abnormally low density, an estimated 0.687 kg/m^3, it's density is less than the H2O, commonly known as 'water.'
So, if Saturn could solidify, it would indeed float in a collection of H2O molecules.
