Answer:
Diseases were often spread along trade routes.
Explanation:
Trade routes such as silk route across Asia, Europe, and Africa was use to exchange many things such as food, ideas, clothes, animals and diseases.
A negative consequence of trade routes is that during trade and movement of people from one place to other, spread diseases such as bubonic plague, measles, and small pox. these diseases have no cure at that time and affected the population across badly.
Hence, the correct answer is "Diseases were often spread along trade routes."
