How does the rate of a proportional tax change with income? A.
The rate increases as income increases.
B.
The rate remains the same, even if income increases or decreases.
C.
The rate decreases as income increases.
D.
The rate decreases as income decreases.

B.  The rate remains the same, even if income increases or decreases.

Explanation:

Proportional tex means that the rate of taxes is the same for everyone. It does not change based on someone’s income. Those who earn more pay the same amount of annual taxes as those people whose incomes are low. This system is also called flat taxes.

Some say that this is the way to motivate people to work and earn more, so they can lose less money proportionally to the taxes. Others criticize the proportional tax system as unfair to those who have low incomes.

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.