Why did the Inca contract the Europeans' diseases and not the other way around? Please answer ASAP ill make you the brainliest

Which of the following could be seen as a weakness of a two-party system? a. the two-party system limits voters' options in electing officials.b. the two-party system limits debate on issues.c. the two-party system limits the range of solutions that will be considered.d. all of these are weaknesses