Why was he chosen by the Ming Dynasty to lead the Indian Ocean maritime expeditions?

Please include the following in the essay:
Who was Zheng He?
Why was he chosen by the Ming Dynasty to lead the Indian Ocean maritime expeditions?
Analysis of the goals of the expedition
Zheng He: diplomat or enforcer in the Indian Ocean?
Explain the Ming decision to abandon Hes explorations
Impact of Zheng Hes explorations