Complex sentence: It is the country's most important commodity and mineral resources seaport, as Johor is home to a large number of major commercial plantations, and Pasir Gudang is home to a majority of Malaysia's resources refineries.
Split into simpler sentences: It is the country's most important commodity and mineral resources seaport as Johor is home to a large number of major commercial plantations. The port is also home to a majority of Malaysia's resources refineries.