Answer:
the answer is B i did this test
Explanation:
Answer:
Vaccinations
Explanation:
For example, if a disease has an R0 of 18, a person who has the disease will transmit it to an average of 18 other people. That replication will continue if no one has been vaccinated against the disease or is already immune to it in their community. So if you have (for example) a vaccination then you're less likely to get it, resulting in a lower R0
The only independent variable in this experiment is the amount of nitrogen Sarah uses. All of the other variables are dependent on other factor and processes, but Sarah controls the amount of nitrogen that she uses for each plant.