30 ponits
explain how and why european diseases did more to destroy the people of south america (inca, maya, aztecs) than the wars and take over by the spanish and the portuguese.

In order to fully understand the answer, i'm going to explain a bit of the simple biology behind it first. in your body, there are things called b cells and t cells. these cells are part of your immune system. specific cells under these groups are called memory b or t  cells. whenever you get sick, these memory cells remember not only what the illness looked like, but also how you recovered. that way, in the future, you have an immunity to the disease. while you may still be able to get it, especially if it mutates, you will get over it quickly and the effects of it won’t be as severe. over time and as generations pass, races are able to build up immunities to certain diseases in their homeland regions.

now, this relates to the question, because in short, diseases were more deadly than wars, because they were able to spread and infect a far greater population. in war, there were two or more sides and while some may have had certain disadvantages, all were able to fight back in some way. they had some sort of defense. however, the natives had no defenses against the diseases. they had never been exposed to them before, so they had no memory cells to give them immunity. along with having no immunity, they also had no idea what was going on. they didn’t have the knowledge to cure the diseases, leaving them even more defenseless. as diseases are typically contagious, they were able to spread throughout the native population, leaving behind a trail of dead bodies. 

so, even though guns perhaps killed the natives in a shorter period of time, the natives were able to fight back. they themselves could ride horses and shoot arrows. they were able to assemble armies, that, while weak, were still strong enough that the conquistadors had to enlist from rival tribes to defeat them. however, against diseases, they had nothing.