Why did parliament keep trying different ways of raising revenue from the colonies?

Parliament kept trying different ways of raising revenue from the colonies to finance the debts they incurred in recent years. They incurred a huge debt financing the Seven Year's War and were trying to get the colonies to help pay for it.

i think the answer is  a or c

Explanation:

Experts think the fluctuations of the Indus had a major impact on Mohenjo Daro. It whipped back and forth across the plains, causing floods that destroyed the agricultural base of the city. Trade and the economy were disrupted. Hundred of villages may have been destroyed by floods or by rivers carving new channels.