Answer:
Microbial mats.
Explanation:
Microbes formed sheets that were able to capture layers of sediment is called microbial mats. These mats of microbes provide good fossil evidence to the researchers. These microbial mats consist of bacteria and archaea which is considered the earliest form of life on earth. These microbial mats grow on moist places as compared to dry environment. About 3,500 million years ago, these microbes are the most important members of earth and maintainers of the ecosystems.
