I think its d all of the above
<u>Stromatolites are layered mounds of calcium carbonate that were deposited by algae during the Precambrian time.</u>
Answer: Option C
<u>Explanation:</u>
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.
<span>More than half of Africa's source of energy comes from coal. Its coal production and waste led to several environmental problems like wildfire and diseases. In one mine leak incident in Africa, last 1953 brought poison on the water supply killed thousands of marine life.</span>
