21. The main purpose of the passage can best be described as an effort to:

Answer and Explanation

Your Answer is

Correct Answer is A

Explanation

This article talks about the background of the era when star trek was broadcast. It was precisely because of the background of the era and the characteristics of the TV series that it became very popular. and its impact on the publishing industry.

Item A: "Explains why and how star trek has been popular (endure)", which is in line with the main purpose of the article.

Item B: One-sided, just a description of individual paragraphs.

Item C: There is no mention of changes in the plot.

Item D: There is no comparison of the various carrier forms of star trek.