Answer:
Vaccines have been around since 1796 preventing people from diseases and decreasing death rates. I believe due to the modern vaccines and medicine people have been living longer than life expectancies in the 1700's and 1800’s, which was between 30 and 40 years. Vaccines train the human body to recognize viruses or bacteria and the antigens (molecule capable of inducing an immune response) will start attacking the virus or bacteria before it tries to spread and cause sickness once it is has recognized it. However, vaccines are not always 100% safe because they can come with side effects. For example, the Hepatitis B vaccine had a severe allergic reaction, called anaphylaxis which caused difficulty breathing, dizziness, and skin rashes for a few people.
Homelessness are social problem that impacts the health of a community for they are prone for a broad range of acute and chronic illnesses because they lack proper nutrition, good hygiene and they could be deprived of medical assistance.
Once they are sick, they could spread the infection to one community to the other because they have the tendency to hop on one place to the other where they can take shelter. Therefore, they could be a carrier of bacteria and viruses that will put the health of a community at risk.
Random. Hope this helps:)
I’m pretty sure your talking about years so it depends on the person but it normally doesn’t happen right away so I’m gonna go with d and if it’s not all my family might have mouth and throat cancer
