The correct answers are:
- yo form
- since Spanish is a phonetic language, the spelling change is necessary to maintain pronunciation when the preterit ending is added
In the preterit, -car, -gar, and -zar verbs undergo spelling changes in the yo form to preserve correct pronunciation. For example, "buscar" becomes "busqué," "llegar" becomes "llegué," and "empezar" becomes "empecé." These changes help to avoid challenging consonant clusters or maintain the sound of the verb root.