They are using a smallpox germ that is weak.
smallpox and others
Improved knowledge of the atom via new experiments and development of new theories (e.g. quantum mechanics).
smallpox
If smallpox were to break out anywhere, it has to be reported. It's to dangerous not to be!
smallpox
England's treatment of the colonies changed after the Glorious Revolution. A new king was instated who set forth more restricting policies on colonists.
smallpox
he changed laws and made new promises and less merciful laws
It has mad them even smarter and have made them live.
Cells change (differentiate) substantially in morphology during embryonic and fetal development.
New hardware technologiesNew processor architecturesNew operating systemsNew software development methodologiesNew software development toolsAll of these changed in someway between computer generations.
Yep...especially if you were a 'native american'. Smallpox was a major factor in the decimating of number of American Indians, as they caught it from non-natives.