Which geographic factor has most affected the environment in Northern Africa

Using complete sentences, explain the differences between a command economy and a market economy. what type of economic system is created when these two systems are combined? what are the benefits of combining these two systems?

"water seeps into rock cracks and dissolved minerals there.the solution travels through cracks in the. eventually concentrating into large crystals." which process is that

The current is like a stream or river in the ocean true or false