Question

What are stromatolites?

eukaryotes with nuclei that were formed by a single cell or many cells during the Precambrian time

soft-bodied organisms resembling the types of jellyfish, worms, and coral that live in the oceans today

layered mounds of calcium carbonate that were deposited by algae during the Precambrian time

Answer 1

a calcareous mound built up of layers of lime-secreting cyanobacteria and trapped sediment, found in Precambrian rocks as the earliest known fossils, and still being formed in lagoons in Australasia. C

Step-by-step explanation:

Answer 2

Stromatolites are layered mounds of calcium carbonate that were deposited by algae during the Precambrian time.

Answer: Option C

Step-by-step explanation:

Stromatolites are the deposit of the layer which is mostly of limestone and these are mainly formed by the blue green algae which are only one celled organism of primitive times.

The features of these are that they are normally thin and have layers that might be either light or dark in color and are either flat or some of them even have a shape of a dome.