Why are repeated trials required before accepting a hypothesis as true?

What is the author's purpose in this passagea. to remind people to avoid individuals who occasionally display bad manners.b. to encourage people to embrace the feeling of superiority over others.c. to persuade people to demonstrate good manners at all times.d. to convince people to freely express their emotions.

Wymyśl jak wyginęły smoki. napisz opowiadanie 8 zdań minimum. daje naj pls to na jutro ; _:

Do the certificate in a summer course give credits? if so, how many credits? and also, could you tell me which are the summer course and schools you know that give credits?