The most significant point in determining the success of civilization was the east-west alignment of Eurasia versus the north-west alignment of other continents. The east-west alignment, allowed the civilizations ,which settled in Eurasia to grow faster. These civilizations had the advantage that the all had the same climate. “Day length is constant throughout the year at the equator, but at temperate latitudes it increases as the months advance from the winter solstice to the summer solstice.” (184) This allows for plants and animals to spread because since Eurasia is usually in the same latitude lines. It’s not like in America since it has a north-south alignment. This means that the civilizations have different latitude lines. This caused many problems since there was a lot of climate change also lots natural barriers. In Eurasia, there was this huge amount of area. This made it easy for Europe to share their ideas with Asia and vice versa. In the other hand Mesoamerica and South America only had a little channel through which they could join. Also they had established barriers, the tropics in Central America, which did not let them to interact.Many would think that germs actually might be a bigger point for determining people triumph. Even diamond states that “Eurasian germs played a key role in decimating native peoples in many other parts of the world,” (213). When I see this report, I wonder how germs even got to Europe. The only reason is due to the creations of civilizations. Civilizations were created due to the ideas that were developed in Eurasia of irrigation systems and specialization. This means that the ideas were actually spread because Eurasia is extended from west to east. Populations such as Mesoamerica could of actually also develop diseases, but for them it took longer because they did not interact with other civilizations which means that their people took longer to get. Jared Diamond states that, “Andes, Mesoamerica, and the Mississippi Valley never became connected by regular fast trade,” (212) In Eurasia there something called the silk road which developed around 200 BCE and this route allowed civilizations to exchange knowledge, technology and of course germs. Also many of the diseases that killed many of the Americans actually came from animals. If we take a look at the chart in page 207 it shows the different diseases that animals transmitted. These animals were able to spread through Eurasia quickly because the weather going west to east was similar these animals were able to adapt. There civilization such as Tasmania, Australia, and New Guinea that were completely isolated and could not developed such diseases because they were never able to grow so big or interact with other civilizations. Now a day’s people are able to communicate with each other through the use of language. Language plays such a big role in present time that it will be extremely difficult for people to communicate without words. Writing then should play an important role in the success of civilizations? I think this is right, but I think even though some civilization like the Mexicans developed writing they still were not very successful. They were not successful because they were not able to extend this language to near society and thus develop and stringer civilization. “The independent invention that we can trace in greatest detail is history’s oldest writing system, Sumerian cuneiform” (218). The oldest writing system was created in the Fertile Crescent in Eurasia and from there on, “all other peoples who have developed writing since then have borrowed, adapted, or at least been inspired by existing systems,” (218). Then if we can observe in page 219 the table indicates how 17 different types of writing were developed in the world, and 13 of these were developed in Eurasia. This is not just coincidence, people living in Eurasia were able to communicate and distribute writing to the rest of the Old World. They were able to do this since it was easy for this continent to maintain communication between each other. In the Americas “Mexicans Indians,” (218) developed a writing system “before 600 B.C,” (218) but they were not able to extend this idea with the rest of the continent. In the Americas Mexico was isolated from North America by the hot desert between México and United States. The temperatures were too strong for Mexicans to navigate to the other side. For Mexicans to go south it was also tough enough to “the intervening tropical climates,” (188) that waited and the little road that connects South America with Mesoamerica. Societies were able to get better by adapting new information, technology, germs and other inventions from other societies. The adapted these new inventions through “peaceful trade, espionage, emigration, and war,” (256). These different ways of distribution were all possible for the Eurasian continent because they were able to interact with different societies. The Europeans were able to obtain a lot of information from the Arabs during the Crusades which began in 1000 AD. The Silk Road helped diseases and ideas to be traded as well. Also you can show cultural diffusion happened when the Mongols took over of a lot Eurasia. They were a key ring that helped the spread of Islam. Mongols moved around a lot and as they took over places they obtained knowledge and one of the things they learned was the Islam religion. These events did not result in the Americas because civilizations were not able to communicate with each other. The west-east alignment is the most important factor that led to the success of civilization.