TEXES Science of Teaching Reading Practice Exam - Prep & Study Guide

The part of the word 'apple' that represents the onset is 'a.' In phonology, the onset refers to the initial consonant or consonant cluster of a syllable. In this case, 'a' is the initial sound in the syllable 'ap,' which works to create the onset.

While 'pp' makes up the consonant sounds within the syllable, the onset specifically relates to the very beginning. 'ple' denotes the final portion of the syllable, which usually contributes to the rhyme but does not factor into the onset of the word. Thus, the correct identification of the onset is the initial sound 'a,' leading to a better understanding of how syllables are structured and how phonemes operate within spoken language.