Cells are the basic units of structure and function in living things, all cells are produced from other cells, all living things are composed of cells.
The correct answer would be "Density is the amount of matter in a certain volume"
The correct answer is they are produced by cyanobacteria.
Stromatolites are being produced by cyanobacteria.
Stromatolites are termed as layered mounds, which have columns and also sheet like rocks which are originally formed with growth of layers.
Lichen stromatolites is a type of stromatolite which is formed by layered structures rocks and they are formed above water.
