The correct answer is - Olmec.
The Olmec civilization was existing in the period between 1,200 BC up until 400 BC. This civilization developed in Mexico, more specifically in the south-central lowlands of the country. The Olmec were a very advanced civilization for their time, and they are considered as the civilization that set the basis for all the others civilizations in Mesoamerica, like the more ''famous'' Maya and Aztec civilizations. The trademark of the Olmec is the big stone heads, about which there's lot of debates about their purpose and means.
<em>open lake </em>is a lake where water constantly flows out under almost all climatic circumstances. Because water does not remain in an open lake for any length of time, open lakes are usually fresh water: dissolved solids do not accumulate. Open lakes form in areas where precipitation is greater than evaporation. Because most of the world's water is found in areas of highly effective rainfall, most lakes are open lakes whose water eventually reaches the sea.
<em>closed lake </em>(see endorheic drainage), no water flows out, and water which is not evaporated will remain in a closed lake indefinitely. This means that closed lakes are usually saline, though this salinity varies greatly from around three parts per thousand for most of the Caspian Sea to as much as 400 parts per thousand for the Dead Sea. Only the less salty closed lakes are able to sustain life, and it is completely different from that in rivers or freshwater open lakes.
Answer: B. It is useful for navigation.
Explanation:
The Mercator is a famous map projections that was created by Geradus Mercator who was a Flemish geographer in 1569.
The Mercator is used for nautical purposes and is regarded as the standard map projection due to the fact that the lines of true direction can be represented on it and hence useful for navigation.
The Sahara Desert blankets nearly all of Mauritania, Western Sahara, Algeria, Libya<span>, </span>Egypt<span> and </span>Niger<span>; the southern half of </span>Tunisia<span>; and the northern parts of </span>Mali<span>, Chad and Sudan.</span>
Here is an example! Hope it helps