Final answer:
The corrected sentence uses a parallel structure with all elements following the gerund form: 'Police dogs are used for finding lost children, tracking criminals, and detecting illegal drugs'. Parallelism enhances readability and clarity in writing.
Step-by-step explanation:
To correct the sentence for proper parallel structure, the elements in the series should all follow the same grammatical format. In this case, using gerunds (verb+ing) will maintain the proper parallel structure. The corrected sentence should read Police dogs are used for finding lost children, tracking criminals, and detecting illegal drugs.
Parallelism helps to create symmetry, balance, and can make concepts easier to remember. It is a crucial element in delivering clear and effective written communication. Police dogs are an example of a tool used in law enforcement, as mentioned in FIGURE 7.10, especially within K9 units to ensure public safety by searching for dangerous substances and assisting in criminal apprehension.