<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.
"The vegetation must be able to adapt to unreliable precipitation and excessive heat" is the one interesting feature of the vegetation among the following choices given in the question that is <span>found in the Sahara Desert. The correct option among all the options that are given in the question is the second option or option "B".</span>
Portugal. this is also the reason portugese is spoken in brazil
External contact and intercultural exchange benefitted early civilizations. This is true of both the civilizations of sub-Saharan Africa and those of Southeast Asia.
In the case of Sub-Saharan Africa, one such civilization was that of the Kingdom of Kush. This was established around 1070 BCE. Kush developed in a region known as Nubia, in the Sudanese and southern Egyptian Nile Valley. Much of the success of the Kingdom of Kush came from its interactions with Egypt. Kush was an important producer of gold and ivory, and by trading with Egypt, it achieved great wealth. It also acquired some of the traditions of Egypt, such as the building of pyramids and mummification.
Southeast Asian civilizations also benefitted from trade in their early years, particularly maritime trade. The Austronesian people built the first ocean-going ships. They trade with areas such as Southern India and Sri Lanka. This also connected these people with the cultures of India and China. This trade led to a rise in technological knowledge and traditions. Some of the items that were exchanged in this trade were catamarans, outrigger boats, sewn-plank boats, coconuts, sandalwood, bananas, and sugarcane.
