In the movie, minerva says a dictator's favorite diet is bread and fear. why do you think she meant by that

She meant exactly that. Dictators hold their power on fear and grow stronger the more people fear their regime. It's artistically said sentiment as the dictator needs bread for physical sustenance and fear for political sustenance.   In order to keep control over people the dictator makes the people fear him.

Heritages are considered as the precious wealth Of the nation because, the heritage structures like monuments, forts, market e.t.c bare witness