What determined history and the fates of humans on different continents was geography, as Diamond makes clear. However, the most important factor within the geographical category was the alignments of the major continents. Eurasia and its early inhabitants had an advantage over Mesoamerica and Africa because it is lined up in an east-west axis instead of a north-south one. This leads to remarkable differences in determining which region can spread its people, animals, and crops faster or at all. Diamond explains that, "Localities distributed east and west of each other at the same latitude share exactly the same day length and its seasonal variations. To a lesser degree, they also tend to share similar diseases, regimes of temperature and rainfall, and habitats or biomes"(p.183). With this said, it should be clear to many of why Eurasia received the better part of the deal in geographical terms to be able to sustain faster advancin early societies. In Eurasia farming just had to begin spontainiously in one place, such as the fertil crecent, and from the spread to other places east and west of it and the plants that were farmed spntainiously could survive in those other localities. However, when it comes to Mesoamerica and Africa, they too have areas that are est and west of each other but to a much lesser extent not enough I believe to compete with that of Eurasia. Their alignments from north to south bring about the complication for farming to begin spontainiously in ares north or south of each other due to the differences in climate, day length, and seasons. Perhaps the idea of farming could spread but not the plants because they wouldn't survive since they are used to those specific factors and how they play out in their specific areas. Once the idea arrived to a different location, the process of domesticating local plants had to begin over and over again unlike in Eurasia where the same plant could survive.
Plants are food and food is needed for life. Hence, it makes sense that animal domestication in an area would most of the time come after there was food to feed those animals. As for language and writting, these can only come once a society has become a sedentary society in which some produce food and other have time to develop such systems. Sedentary societys can only exist once there is enough food grown to feed many and in order to produce enough food, animal help is needed. This means that farming is the root of civilizations. Aparently, the east-west alignment of Eurasia spread farming faster, which made societies or civilizations spring up faster.