How to fix flashing folder with question mark on mac without cd?

Which of the following had the greatest influence on opening the internet to the generly public

Drag each label to the correct location on the imagelist the do’s and don’ts of safeguarding your password.keep yourself loggedin when you leave your computer.don’t write your password down and leave it whereothers can find it.share your password with your friends.each time you visit a website,retain the cookies on your computer.use a long password with mixed characters.

Ihave been given the number of guns per 100, and the total firearm-related deaths per 100,000. i have to find the actual number of guns per country and actual number of gun-related deaths. if somebody could show me how to do 1 question, i can finish the rest, i am just confused. tia