In the 1970s, with the rise of work by coppola, spielberg, george lucas, martin scorsese, and others, a new breed of director emerged, leading to a wave of productions, including close encounters of the third kind (1977), star wars (1977), raiders of the lost ark (1981), and e. t.: the extra-terrestrial (1982). because of high marketing and production costs, the major studios have increasingly come to rely on these types of films to keep themselves profitable.

The answer is a wave of Blockbuster productions

Explanation:

After the 1970, the graphics and computer based technologies were somewhat advanced and more applicable in movies.

Moreover, the emerging new breed of science fiction and fantasy directors gave good stories that could be combined well with the available technologies to produce movies that gave a "magical" and "surprising" effect to the audience.

After 1970, most of the movie studios relied on science fiction genre to make more profitable Blockbuster movies. Even today the science fiction/fantasy movies are the most profitable and highest grossing.

some notable example are,

a. the ku klux klan

they were aganist african americans and did some bad things to them : ( hope this

its c not d   tell me if that´s correct