The corrrect sentence here is 'Ramona ha estudiado bastante para el examen de ciencias'. It is a verb form.
The present perfect tense is a verb form used to describe past events and/or situations that have been present.
In this case, the Spanish present perfect tense is written as 'ha estudiado' (she has studied).
The Spanish verb 'estudiar' means 'to study' in English (in this case, Ramon 'ha estudiado').
Learn more about the present perfect tense here:
https://brainly.com/question/26622963