Explanation:

Democracy is considered as the best form of government because: The rulers for the country is directly elected by people. Its the government for the people, by the people. It make us allow to correct our mistakes.
Water boils and evaporates at 100° C.
All radii of any given circle are of equal length.
Myopia, also known as short-sightedness or near-sightedness, is the most common disorder affecting the eyesight and it is on the increase. The causes are both genetic and environmental. Experts have now made important progress towards understanding the mechanisms behind the development of the condition.
Hence, option 3 is the correct answer.