Separated by thousands of miles and vast oceans, Mesoamerica and Mesopotamia both developed writing systems independent from one another. They were not aware of each other, and certainly didn't cooperate or fight. The evolution of writing was largely a result of agriculture and the need to keep records of surplus.

The compass was invented in China during the Han Dynasty - approximately two thousand years ago. The compass was refined during the Song Dynasty and eventually spread to Europe by the fourteenth century. The invention of the compass allowed for much more reliable navigation and greatly aided European exploration from the fifteenth century onwards.

There were no major technological or economic breakthroughs between the Neolithic and Classical eras. Agriculture was a major breakthrough that marked the beginning of the Neolithic era, but we wouldn't see any other transformations of that significance until the Industrial Revolution of the 18th and 19th centuries. Civilizations and populations continued to grow as humans developed in terms of agriculture and were able to support more people. Furthermore, communication networks experienced major growth during the Classical era with development of networks like the Silk Roads, Indian Ocean network, trans-Saharan network, and Mediterranean network.

Aristotle was the head of Royal Academy of Macedon at the time of Alexander's youth, and thus became his tutor when he reached schooling age. Though this relationship has probably been overstated in modern culture, it's likely Aristotle did have some impact on the young prince. Aristotle was also instrumental for work in physics, biology, and many other fields. 

The first domed building to be built in Europe since the collapse of the Roman Empire was the Florence Cathedral, built by Filippo Brunelleschi during the Italian Renaissance. The Italian Renaissance was a period of rediscovery for European intellectuals, including ancient architectural techniques. The Age of Sail, in which millions of Europeans migrated to the Americas, Cortez's invasion of Mesoamerica, the unification of Germany, and William the Conquerors invasion of Britain had dramatic effects on Europeans and their knowledge of the world, but did not lead to the ability to build domed structures.

Gunpowder was invented in China.

Within a few hundred years it had spread all the way through Asia, including India and the Middle East.

When European nations invaded, conquered, and colonized the Americas, gunpowder was a staple of their arsenal. 

Hand cannons are the earliest types of handheld firearms and tend to lack both triggers and stocks; a burning torch would be applied, often by a different person than the one holding the cannon, to a hole bored in the cannon and lined with powder leading down into the barrel of the weapon where packed powder was ignited, pushing forward a projectile with enormous speed. Although over centuries, and from workshops as diverse as Medieval Switzerland, Sinkoku Japan, and Lincoln's United States, arquebuses and muskets were constructed with different attributes, in general all arquebuses and muskets have trigger mechanisms.

Wet gunpowder won't light, regardless the weapon system.

Hand cannons could be held by a single person.

Hand cannon technology was used all over the world, including but not limited to the Middle East and Europe.

Percussion cap technology occurred at the end of muskets being used by professional armies, long after hand cannons and arquebuses became obsolete.

In the 15th century, firearms were used on many medieval battlefields, but only by a small proportion of troops because they were expensive, ineffective, and potentially dangerous to the user; bows and crossbows existed alongside firearms for centuries.

Firearms numbers decreased as the technology became more lethal.

Firearm usage was never a monarch's personal prerogative.

Due to the era’s complete and total lack of anything approaching modern medical knowledge, the majority of Europeans, from nobles and the clergy down to shopkeepers, merchants, and peasants, had no factual idea about the plague’s true cause. Even worse, this lack of understanding extended to the ways in which the disease was spread; even physicians, who lacked knowledge of germs or proper hygiene, could only guess as to how the plague was transferred from person to person. This vast state of confusion only compounded Europe’s fear and panic over the rising sick rate and death toll, as one by one, large population centers found themselves transformed into hotbeds of illness. Desperately seeking any sort of explanation for the disease’s devastation, many people turned to superstitions, extreme religious beliefs, ethnic discrimination, or misguided scientific notions about the natural environment. By far the most popular explanation was that of nameless toxins in the atmosphere – most Europeans believed that unhealthy air was somehow to blame for the plague’s swift spread, although speculation as to the exact makeup of these airborne toxins was varied and essentially baseless. Other individuals blamed earthquakes or volcanic eruptions, which they saw as natural incubators of sickness and disease. Still others turned to religion, speaking out against immorality (such as sexual promiscuity, poor church attendance, and greed) as the instigating factor which had caused God to send down the Black Death as punishment. Due to a pervasive cultural tide of anti-Semitism, many people targeted Jewish citizens as spreaders of the disease as well, but this persecution was more general in nature, and not as particular in its nature as the answer option provided, it was also not as widespread a notion, particular to the plague, as the correct answer option provided.

Milanese armor workshops were so successful that for generations most European armor was heavily influenced by Milanese designs.

Milan's power waxed and waned throughout the middle ages, but it never conquered a large territory and declared a Milanese empire.

Militarily, the Turks were in a period of strength and expansion during this period, conquering Constantinople; they were not threatened by tiny Milan.

The royal houses of Europe desired Milanese armor and armor designed in that style, they did not band together to destroy the source of such advancements.

Most firearms of the period could not pierce plate armor, in fact the final test for all professionally made plate armor was for it to be shot at within close range to prove to a customer that firearms couldn't penetrate. Mounted knights in full plate armor were threatened by firearms, however, because their horses could be shot out from under them.