Final answer:
Muslim merchants favored camels over horses because camels could carry heavier loads and required less water, crucial for desert travel.
Step-by-step explanation:
Muslim merchants traveled on camels rather than horses for several reasons. One significant advantage is that camels could carry heavier loads and required less water than horses, which was crucial in the desert environment. Camels were especially adapted to this harsh landscape, with their unique splayed foot structure allowing them to walk easily on soft, sandy terrain and their ability to go for extended periods without water.
Camels also played a vital role in military expeditions by enabling Arab armies to cross deserts and launch sudden attacks. The camel's endurance and ability to transport heavy supplies without needing frequent stops for water made them indispensable for maintaining long-distance trade routes, particularly the trans-Saharan trade, which thrived between the ninth to fifteenth centuries.
Option 'b' is the correct choice for why camels were better for travel than horses in desert conditions: Camels could carry heavier loads and required less water than horses.