Which has been in force since 1975. What is the grammatical name and function?

the correct answer is:

from context clues heliotrope is probably a flower.

a heliotrope are peruvian plants that have small purplish plants.

the answer is a.

enlisted

i believe it is the first choice (1.)

because the major theme is(“both the wild and civilization have rules.”)

and also as u said,( based on what buck learns within the call of the wild, "both the wild and civilization have rules".this is true of humans within society as well.