Final answer:
The exception to the correct statements concerning Archaea is that some are producers. Archaea are prokaryotic microorganisms that are single-celled, have DNA, and lack a nucleus. They are most closely related to bacteria, but unlike bacteria, archaea do not have the ability to produce their own food through photosynthesis or other means, so they are not considered producers.
Step-by-step explanation:
The exception to the correct statements concerning Archaea is that some are producers. Archaea are prokaryotic microorganisms that are single-celled, have DNA, and lack a nucleus. They are most closely related to bacteria, but unlike bacteria, archaea do not have the ability to produce their own food through photosynthesis or other means, so they are not considered producers.