I have to write the prepositional phrase, the word it modifies, and whether the phrase is an adverb or adjective

Many factory robots are arms on moving rails.
Prep phrase on moving rails
modifies are
adverb?

Robots handle materials that would cause damage to human flesh.
Prep phrase to human flesh
modifies damage?
adjective?

"On moving rails" describes and modifies the noun, "arms."

Your answer for the second one is correct.