Which of the following modern holidays is a mixture between an ancient Celtic festival and Christian celebration? Christmas
Halloween
New Year’s Day
St. Patrick’s Day

Halloween is the mixture of Celtics festival

Halloween

is the answer

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.