<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.
I agree on that. it's not like there is completely no force of gravity acting on them (I mean if they're still around the earth) , it's that it's so little that they can't even notice it. they'll float around and they seems like they have no weight. this is called weightlessness.
900 miles west is actually not that far - actually around 500 miles west from Khartoum, it's still Sudan! And exactly 900 miles west of Khartoum is in the middle of Chad -so the correct answer is Chad!!!
Chad is also the country that borders Sudan to the West.
Answer:
In the 1960s, when there was a deadlock on sanctions against South Africa because of the opposition of its trading partners, the United Nations launched an international campaign against apartheid to encourage committed Governments, non-governmental organizations
Explanation:
If this dosen't make sense i can help more im in high school so i know this stuff