Which of the following is a mineral or combination of minerals mined for the production of metals?
a.
ore
b.
papyrus
c.
regent
d.
none of these

A. Ore is the correct answer.

Explanation:

A naturally occurring sediment which contains minerals and economically important elements that can be profitably extracted is known as ore, they are extracted through mining and then refined to get the elements. The concentration of the ore and its form affect the cost of mining.Oxides, Sulfides, Silicates are ores. Ore's are formed by different geological processes and the process is called ore genesis.

crop rotation kepy different plants in the soil instead of once constintly. when switching out plants you have different nutrients being absorbed at different speeds and different roots growing differently therfore the spoil and water flow have to adapt and carry fresh nutrients to carry the constant changes that were going on in the soil.

by improved communication.