The term decrescendo tells the musician to perform what action?

The term decrescendo is an italian musical term. When the musician is following the musical notes, they might encounter with the reference decresc. which indicates to perform the action of reducing or decreasing gradually the volume or intensity of the sound to prepare for a shift. The symbol for decrescendo is a narrowing angle.

we need the diagram to answer this correctly.

the factors that the economies of the muslim empires prosper were:

1- land trade routes-located between three continents  

2- sea trade routes

trade contributed to the spread of muslim empires, and with that islamic culture led to a growing feeling of internationalism resulted in the transfer of technology, science, and other cultural forms.