Does anyone understand this? Pls help

What was the most difficult obstacle to overcome in the creation of an autonomous state after indian independence was achieved? a british willingness to go to war to retain the region b. religious differences between hindus and muslims c. ethnic differences between tribal regions d. indian princes' inability to decide on a format of government

During which era in earth's history were the first insects? mesozoic precambrian cenozoic paleozoic

What is the thickest layer of earth called?