Ore deposits of the element do not require extreme concentrations because it is one of the most abundant elements in the earth's crust.

Ore deposits of the element Aluminium do not require extreme concentrations because it is one of the most abundant elements in the earth's crust.
Aluminium is the most common metal in the Earth's crust.
However aluminium can not be found free stand alone. All of the earth's aluminum is combined with other elements to form compounds.

Aregion is an area of land that has common features. these features can be natural, such as climate or landscape. they can also be artificial, such as language or religion. the xinjiang uyghur autonomous region, above, is an area of china inhabited by uyghurs, a muslim group with ethnic ties to turkish people.

Well, a and b together would be negative. b alone would also be negative.