Which statement about a stated theme is true?
a.
it is the same thing as the writer's worldview.
b.
it must be guessed by the reader.
c.
it is described in words by the writer.
d.
it is shown through images and symbols in a poem.

sentence lenght varies according to word choice.you select which word to use and that will require to use other expressions that collocate with the word chosen.sentence length will vary   according to the choice of words you make to express your ideas.  

awnser: alliteration, assonance, onomatopoeia.