When researchers observe and describe a current condition and look to the past to try to identify the possible causes of the condition, it is called a

Causal-comparative studies

Explanation:

Casual-comparative study is the research that is carried out by distinguishing and contrasting between two of more communities of people based on evaluating the impact caused by independent component on the dependent component.

Research included comparison along with co-relating the variables. It helps in understanding and studying about cause-and-effect that takes place in different experimental situations.

the first settlements began along the huang river because of the importance of the huang river in the beginning of china. it goes back to the story, “the tale of emperor yu”, which references the tale of the great flood, which was caused by the huang river and was believed to create and influence china’s making.

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.