In a scientific study, a conclusion can
a. state a theory.
b. ask a question.
c. prove a hypothesis.
d. support a hypothesis.

D support a hypothesis

A conclusion in scientific research summarizes the results obtained from the data of the experiments conducted which can be in support of the hypothesis or can be contradictory to the hypothesis. A conclusion could be defined as summing up of the arguments to draw inferences from the research conducted however pointing null hypothesis is also very important because both accept, and rejection of null hypothesis provides very useful information

they can increase to boost the enonomy.

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.