Final answer:
The verb 'repetir' is conjugated to 'repita' in the subjunctive present tense form for third person singular (el/ella/ud). Such verbs that end in '-ir' with a change in the root (from 'e' to 'i') in the present tense typically follow this pattern.
Step-by-step explanation:
The verb 'repetir' in Spanish belongs to a group of verbs ending in '-ir' that have a change in the root in the present tense. Specifically, it changes 'e' to 'i'. When conjugating 'repetir' in the third person singular (el/ella/ud) form in the present subjunctive, the same root change applies and you obtain 'repita'. So, if we use it in a sentence: 'Espero que él repita la lección hasta que la comprenda.' which means: 'I hope he repeats the lesson until he understands it.'
Learn more about Subjunctive conjugation