How does development of gather speed ?​

Speed meaning momentum I would think you mean. And an inanimate concept of development gathers no momentum. I think you are asking how some team of people working on a development, gather momentum with their effort? Which of course depends on the team & the discipline of the effort. A team trying to gain momentum with their project in medicine would be very difficult indeed. Too many safeguards in place to stop momentum. Some new website concept might be hard to restrain it’s momentum. So since the question is so general & open ended, it is almost unanswerable. Being in the single category ‘Speed’ seems to deal with physics. I still believe the question is about the human construct ‘project development’ rather than physics.

Answer From Gauth Math

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.

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.