The countries currently on stage 4 of demographic transition model are.. Argentina, Australia, Canada, China, Brazil, Singapore, South Korea, U.S. , and most of Europe.
<span>A method of processing coal to remove contaminants by mixing coal in a solution of potassium permanganate in a selected concentration range, rinsing the coal, mixing the coal in a solution of ammonia hydroxide in a selected concentration range to cause the solution to be brought into contact with the surfaces and pores of the coal, discharging the processed coal from the second reaction vessel, monitoring the process to detect when the concentration of aqueous ammonia in the second reaction vessel has fallen below the selected range, and feeding aqueous ammonia solution with an ammonia concentration in or above the selected range to the second reaction vessel to return the solution to within the selected range.</span>
<span>Their progress and wealth is highly dependent on the harvests, and
the price of grain. They probably have to import some industrial
products and if they had a bad year (weather, other catastrophies, poor
technology) they can't get the necessary amount of industrial products
in exchange for their surplus e. g. in grain. </span>
A divergent Plate boundary is where new ocean floor is created.
Extra: A convergent plate boundary (Oceanic-Oceanic, Oceanic-Continental, Continental-Continental) is where crust is destroyed.