Explain why the colonies which were ruled by the portuguese gained their independence using armed forces

 Portugal was a fascism that clung firmly to its provinces, and furthermore wasn't invaded during WW2, so didn't lose a portion of its provincial power. However, its colonies began to revolt during the 60s-70s too. It battled long counterinsurgency and there was a significant development of the Portuguese military, and ultimately it took an overthrow in Portugal to overturn the current system to end the pioneer wars.

answer; (d) one tectonic plate plunges beneath another; (most common,convergent boundaries)

b) to encourage free trade