Why are the palms of the black's ligher?

What type of figurative language is used in this passage from "letter from birmingham jail"? just as the prophets of the eighth century b.c. left their villages and carried their "thus saith the lord" far beyond the boundaries of their hometowns, and just as the apostle paul left his village of tarsus and carried the gospel of jesus christ to the far corners of the greco roman world, so am i compelled to carry the gospel of freedom beyond my own hometown. allusion symbolism imagery metaphor

Nutrients are chemical substances that are absorbed by the body through the process question@ask for

Agood persuasive essay topic cannot be a. a fact b. debatable c. something somebody else has already written about