What is volcanic soil

Volcanic soils form by weathering of volcanogenic materials. This soil group shares unique physical and chemical properties largely attributable to the formation of poorly crystalline and noncrystalline minerals, and the accumulation of organic matter.

Explanation:

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answer: 20 percent

the fish culture has become a developing commercial practice in developing countries which is already prominent in developed countries of the world. the major fish protein demand is being supplemented in developing countries is   fishing to meet the needs of the growing population. therefore, in some developing nations, the percentage of animal protein from fish in the diet can be as high as 20 percent.