Environment & Ecology · Geology and Biodiversity

With reference to Stromatolites, consider the following statements: I. Stromatolites are organo-sedimentary structures formed by the activity of algae and cyanobacteria. II. They are exclusively found in deep ocean environments. III. Stromatolites were abundant during the Precambrian era. IV. The presence of stromatolites in the Himalayas indicates that the region was once part of an ancient marine environment. How many of the statements given above are correct?