Misc: Which French artist, in 1883, gave up his job as a stockbroker to paint full time?

Questions

Every human first spent about half an hour as a single what?

Every photograph of an american atomic bomb detonation was taken by who?

Every square inch of the human body has an average of 32 million ______?

Which company, during the 1984 Super Bowl, aired what is considered one of the best commercials in TV history?

Excluding man, what is the longest-lived land mammal?