The appearance of banded iron layers in the rock record between 1.08 and 3.8 billion years ago reflect the alteration of oxygen-rich and oxygen-poor conditions in the ocean at that time is True.
Explanation:
The banded iron formation of the rock is directly related with the atmospheric oxygen content of that time. The thorough study by the scientists revealed an interesting result. The study showed that about 3 billion years ago, in Canada, there were no oxygen in atmosphere or ocean as well.
This resulted in the increase of the photosynthesizing organisms. The chemicals released from the organisms reacted to the iron of the ocean to deposit iron oxide layer on rocks to form these layers.
