The correct answer is: They are almost identical except for one form.
In the present tense for regular ER and IR verbs in Spanish, the endings are similar for most forms, but they differ in the first-person singular (yo) and the third-person plural (ellos/ellas/ustedes) forms. For example:
- ER verb (comer): como (I eat), comen (they eat)
- IR verb (vivir): vivo (I live), viven (they live)
The first-person singular (yo) and third-person plural forms have different endings for ER and IR verbs.