User blog:Nkbeeching/Eurasian Supremacy based on Geographic Luck?

I recently finished reading a book Guns, Germs and Steel. Its an execelent read that talks about the reason why europe and asia came out as the leaders of the world and not africans, astralians, or american natives, and why none of those continents could have produced the expansionist nations of earth or major deseases that killed off millions. Its all based on 3 factors, geographic positioning based on the horizontal; axis that allowed the easy spread of agriculture and writing throughout eurasia, the plants and animals that were avaliable for domestication in each continent (this being the most important factor apart from geographic positioning), geographic barriers that stopped the diffussion of agriculture. I personally found it a good read, and if it is true what do you all think?