Explanation:
this question is based on your opinion
Well, it depends on how you write. As you may know,a external conflict is a conflict occurring outside, like tornado or fires. A internal conflict is a conflict occurring inside like emotions. You could write about a man surviving on a island, balancing the external conflict (weather, hunger, etc) while still maintaining the emotional conflicts (misses family, difficult to kill animals).
Periodicals
"Short articles" seems to be a hint towards the newspaper industry. Periodicals were newspapers that were published from time to time.