Final answer:
The correct verb form in this sentence is 'puedan'.
Step-by-step explanation:
The correct verb form in this sentence is puedan. The sentence is written in the third person plural, so the verb must also be in the third person plural. The correct conjugation of the verb poder (to be able to) in the present subjunctive form is puedan. Therefore, the sentence should be: Es indispensable que las comunidades indigenas puedan tener sus tierras.
Learn more about Verb conjugation in Spanish