Answer:
vaccination
Explanation:
Louis Pasteur had been working to find a vaccine that would cure cholera in chickens. His lab assistant gave an older, weaker strain of the disease to the birds. When these birds did not die Pasteur began to rethink his ideas a came up with our current method of administering vaccinations.
It’s goes period, colon (:), this thing (‘), and comma I think
Rome's increasing wealth and expanding boundaries brought many problems. The most serious were growing discontent among the lower classes of society and a breakdown in military order. These problems led to a shakeup of the republic—and the emergence of a new political system. I might not know if this will answer your question but it might help.
A lot of people died and wounded
