Question

which sentence is in passive voice? several congressional bills have proposed mandatory labeling of genetically engineered foods in the united states. mandatory labeling of genetically engineered foods in the united states has been proposed by several congressional bills.

Explanation:

In the passive - voice sentence, the subject (mandatory labeling of genetically engineered foods in the United States) receives the action (has been proposed) and the doer of the action (several congressional bills) is introduced with 'by'. In the first sentence, the subject (several congressional bills) performs the action (have proposed).

Answer:

Mandatory labeling of genetically engineered foods in the United States has been proposed by several congressional bills.