What does “marvel” mean in this sentence? “Now the U. S. was joined together, literally and symbolically, by a marvel of engineering and human labor- the transcontinental railroad.”

B. Feat

Explanation:

Transcontinental railroad t connected several states and allow people to travel or distributed product from one states to another with significantly faster time.

"marvel of engineering and human labor" is the phrase that the speaker use in order to express his/her awe.

The railroad was considered as one of the biggest feat/accomplishment In American history, considering how much labor and investment it needed.

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.

answer; education;