Choose whether the main verb in the sentence below is active or passive.

experiments with chimpanzees revealed that the animals were able to imitate humans

The main verb in the sentence is active.

Explanation:

In most English sentences with an action verb, the subject performs the action denoted by the verb. Because the subject does or acts upon the verb, the sentences are said to be in the active voice. However, it is possible to change the order of words for the subject to be no longer active, but being acted upon by the verb or passive. In this case, the main verb is "revelead" and it is active.  The verb is not accompanied by any form of the auxiliary verb to be.

its he tried to add or forgive me but he said forego