Can someone help me with number 2? Please and thank you

The answer for #3 is c but i don't know why

What must happen before a body cell can begin mitotic cell division

You encounter a solution that is acidic and you decide to test it by adding a small amount of a strong acid. the ph lowers slightly but is approximately unchanged, and still remains acidic. what can you say about the solution? a. it is a buffer solution. b. it is not a buffer solution it is a strong acid solution. d. the solution has been neutralized. e. the solution has excess acid present