This sentence contains a parallelism error. When comparing things in sentences, in this case, cities, one must present them in the same way. So, since the first part of the comparison contains the word "in" ("in Barcelona"), the second part of the comparison must also be introduced by "in": "in either Seville or Madrid," instead of "either Seville or Madrid."

This sentence contains an error in parallelism. The verbs "travel" and "stay" must be in the same form. In the sentence as it is presented, "to travel" and "staying" do not match. The correct answer makes both of these terms infinitives: "to travel" and "to stay."

The list in the underlined portion of the sentence, "time management, balancing workloads, and file organization," contains three items which do not describe similar actions with their structure. The three items should match in any list structured like the one in the sentence. The only answer choice that features such a parallel structure is "with time management, workload balancing, and file organization."

All elements in a list should be parallel: they should be of the same structure. Choose the answer that keeps elements parallel: "the recent scandal and the disenfranchisement . . ."

In any list like the one in the underlined portion of the sentence, all the verbs in the dependent clause need to be in the same form to show the subject is doing similar actions. The only answer choice that appropriately features such parallel structure is "changing schedules, switching assignments, and breaking old rules."

The underlined portion of the sentence is incorrect, as any series needs to have a parallel structure, where all elements of the series are written in the same form. "Being harnessed, saddled, and ridden" is the only answer choice that is both correct grammatically and parallel in structure.

This sentence contains an error in parallelism. Specifically, it compares "of good luck" to "by skillful play." The prepositions used in these phrases should match because they are being compared—"more a result of X than by Y" doesn't treat format each item in a consistent manner. The only answer choice that fixes this issue is "good luck than of skillful play," making the corrected sentence "The success of the one-handed touchdown catch was more a result of good luck than of skillful play."

Any list like the one in the underlined portion of the sentence needs to have a parallel structure in their word forms, which the sentence does not have as written. Each item in such a list also needs to be separated by commas; therefore, the correct answer choice is "designing, building, and maintaining a house."

This sentence is correct as written. The sentence relies on the pattern of “not only X, but also Y”. In this case, both of the things that the sentence mentions, “building physical environments” and “fostering policies and practices”, are stated in a way that follows the same grammatical pattern. Both of the phrases use gerunds, or words that end in -ing. So, nothing needs to be changed in this sentence.

The last part of this sentence, “the lawn is mown by her”, sounds awkward because it does not follow the same grammatical structure as the first part of the sentence. The sentence wants to say that the granddaughter helps her grandmother do two things: do the laundry and mow the lawn. The most concise way to say this, and the best way to create parallel structure, is “She helps me do the laundry and mow the lawn.”