The answer to this question is b
the answer is c. I actually just finished studying this. good luck
Fueling factories using something other than wood" since this greatly revolutionized production productivity.
Answer:
(1) Mecca to Constantinople is one such route in spread of Islam.
(2) Mecca to India is second trade route .
(3) Mecca to Alexandria is the third trade route
(4) Mecca to Aden is the fourth trade route.
These 4 trade routes came very handy in spread of Islam.
I think this what what you where looking for... Hope it helps!