Final answer:
The phrase in question does not have parallel structure due to inconsistent grammatical forms in the series. Parallel structure requires the items in a series to be of the same form, such as all adverbs or all prepositional phrases.
Step-by-step explanation:
The phrase "Her parents watched proudly, devotedly, and with love" is not written in parallel structure because the list of adverbs and phrases is inconsistent. An adverb ('proudly'), another adverb ('devotedly'), and a prepositional phrase ('with love') are mixed, which breaks the parallelism. For proper parallel structure, all items in a series should be in the same grammatical form. For example, it could be revised to "Her parents watched proudly, devotedly, and lovingly" to maintain consistent adverbial form, or "with pride, devotion, and love" to maintain consistent prepositional phrase form.
Regarding the provided information, the combination of sentences with 'and' or a coordinating conjunction can contribute to achieving parallel structure, as seen in the revised sentence that underscores mothers' sacrifices. Likewise, verb forms in sentences from past and present perspective can impact the parallelism depending on the tense consistency required.
As in the example of Kennedy’s rhetoric, parallelism is often used for impact and to organize supporting ideas effectively. This is achieved through techniques such as anaphora and epistrophe, which reinforce parallel structure in writing.