Bacterial strain A (met , his-, arg ) is mixed with bacterial strain B (met-, his , arg-), grown in complete media, then plated on minimal media supplemented with histidine. Bacteria grows on the plate, which indicates that .

Plate has all the essential nutrients that is required by the bacteria.

Explanation:

Bacteria grows on the plate, which indicates that the plate has all the essential nutrients that is required by the bacteria. Bacteria needs a type of media for its growth which contains all the necessary items which plays a key role in its growth and development. This plate has a media that contains food which the bacteria use for its growth and development so that's why we can say that  plate has all the essential nutrients that is required by the bacteria.