What Makes an empire powerful?

We have already looked at Alexander the Great's empire and we discovered that it did not last very long. Within a few years of Alexander's death the empire split up into four seperate kingdoms. So we have to ask ourselves what is it that keeps an empire strong? Some historians say its the military or the economy or a strong culture - what do you think makes an empire strong? Make sure you justify your answers by EXPLAINING why you think what you do. Merely mentioning a particular characteristic will not get you the points for this assignment - YOU MUST EXPLAIN YOUR ANSWERS!

What is your responsibility?

You are an anthropologist and you have just discovered the tribe in the above photo while flying over the Amazon Rainforest. This tribe has never had any contact with the outside world. What is your responsibility to that tribe? Do you find a place to land your plane and introduce them to the modern world with all its benefits and problems or do you leave them alone and do everything you can to protect their isolation? Make sure you explain your answer.