What term was given to those who exposed the “dirt” on the problems that existed?

muckrakers

Explanation:

example: jacob riis photographed slums in nyc and wrote a book "how the other half lives" to expose the terrible living conditions.

martin luther king (1929-1968) was an activist for the african american rights, mr. king has a profile of a kind leader that built a tenacity, respect and full of hope future. he was an activist through civil disobedience and no violence pressure mechanisms. he tried to build a more egalitarian and fair society. his efforts carried a reivindication message of the civilian rights to every west corners. for that reason, he won the nobel prize in 1964.