I believe it is D, the reason being is because they form on their own, not from a living or dead organism. It can't be B because that is true, and the same for C. hope this helps, have an amazing day :)
<span>Sputum membranes tests are used to test the lungs, trachea and bronchial canals for pathogens that can have an adverse affect on the lungs. These pathogens can cause infections that can have serious effects on your breathing and all over health.</span>
<span>... beyond africa to asia and europe.</span>
The bladder, the kidneys, the skin, the lungs, the liver, and the urethra.
After mining, to reclaim the land, the depression is filled with rocks then the top is filled with loosely graded soil. Introduction of early succession plants is important before big trees can grow. The early succession plants help in the breaking down of the rocks into soil hence making the topsoil deeper to support trees.