OE:
Parallelism; Grammatical constructionThis sentence provides a list of three conditions Mars travelers would
certainly have to contend with, along with one additional thing they
might have to do—ward off contamination by Martian life-forms. The
items in the list are most clearly and effectively structured in parallel—as
phrases beginning with infinitive verb forms—to endure, (to) avoid, (to)
contend, (to) ward off. Because the sentence introduces all these actions
as something travelers would have to do, repeating the hav[ing] to
construction in the final item of the list is redundant.
A. The phrase having to is not parallel with the other items in the list,
and it unnecessarily repeats the sense of the introductory phrase,
which identifies all items in the list as things travelers would have
to do.
B. The verb form warding is not parallel with the other items in the
list.
C.
Correct. The sentence uses proper grammar and parallel
construction.
D. The participial form contending violates the parallel structure of the
list of infinitive phrases. The reader is misled into thinking that
contending with chemically reactive Martian soil describes what
travelers would have to do to avoid radiation doses.
E. The participial phrases contending with and warding off violate the
parallel structure established by the list of infinitive phrases.
The correct answer is C