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.