Now the porpoises _______ over three buoys.(jump)

have jumped

Is have jumped the correct form of the verb in parentheses?

Yes, that's correct, depending upon context.

It could also be:

Now the porpoises will jump over three buoys.

Now the porpoises are jumping over three buoys.

i need help in a sppech just like the ones with Obama!!!!!

Yes, "have jumped" is the correct form of the verb in parentheses. In this sentence, the verb "jump" needs to be in the present perfect tense because it is referring to an action that started in the past and is still ongoing or has just been completed. The present perfect tense is formed by using the auxiliary verb "have" (in this case, "have") followed by the past participle of the main verb (in this case, "jumped"). So, in order to correctly fill in the blank, the sentence becomes "Now the porpoises have jumped over three buoys."