a pretty long time. those are pretty long words after all, so.
The Feudal system that had previously dominated Europe begins to collapse.
Considered divine punishment, the Black Death (bubonic plague) was one of the largest epidemics that plagued mankind.
In early 1330 the first outbreak of the bubonic plague happened in China. Plague mainly affects rodents, but their fleas can transmit the disease to people. Once infected, the infection to other people occurs extremely quickly. The plague causes fever and a painful swelling of the lymphatic glands called bulbs, hence its name. The disease can also cause blemishes on the skin that first have a reddish color and then turn black.
A. Spanish conquistadors bring their horses with them across the Atlantic. Some horses escape or swim to shore after a ship sinks. The Plains Indians become expert horsemen and buffalo hunters.
This was certainly not intentional since hardly the conquistadors would want their enemies to be stronger.
B. B. Rats are aboard European ships coming to the Americas. The rats spread disease and hunt unknown numbers of smaller animals to extinction.
This is hardly intentional. Rats were almost unavoidable back then and the Europeans just did not care much about them. They weren't thinking about how the rats would cause trouble in the Americas. They were "just rats".
So the only intentional one is:
C. Columbus brought pigs to the Americas on his second voyage. The pigs provided a valuable source of food for a growing population.
Columbus brought pigs for them to serve as food eventually and so they did.
I think the answer is c. contemplative