Comma, No Comma?

My favorite novel The Lord of the Flies has been adapted into a film twice.

My favorite saying is from an anonymous student: "be afraid, but do it anyway."

Research states that eating seven hundred apples a day is problematic.

Women who believe candy should be outlawed recently held a rally in Washington DC

History often celebrates brave people who try to challenge social injustice.

The Mississippi River which flows North to South is longer than any other river in the US.

I would have won, but something beat me: my own arrogance.

It is a well-known fact: employees who engage in harassment will be fired.

Albert Einstein believed in aliens because he said: "I do not think we are alone in space."

Pollution is toxic for one major reason: it exemplifies our striking disinterest.