A vaccine can help keep people healthy and protect them from a certain virus. For example people in the United States get the flu shot when they get this shot the vaccine wont magically get rid of the virus but rather help them fight it off and protect them in the future if they keep up to date getting the vaccine
The best example that illustrates a sensitive period is
letter b, where the child tries to learn in speaking a second language because
this is considered to be a sensitive period in which is the period for a
development of new opportunities that a child could learn in which learning to
speak a second language is considered to be a sensitive period.
Answer:
c is the answer............
You forgot to add the answers but a non living factor that could contribute could be something like temperature.