Step 1: Understanding the Concept:
Coordinate elements in a series connected by coordinating conjunctions must maintain parallel grammatical form.
Step 2: Detailed Explanation:
The habitual actions performed by the subject ('she') require simple present tense third-person singular verbs:
'reads a book (verb 1), sings a song (verb 2) and says a prayer (verb 3)'.
The participial form 'singing' in the original sentence violates parallel structure.
Step 3: Final Answer:
Hence, the correct parallel phrasing is 'Reads a book, sings a song and says a prayer'.