What is true for an energy resource with a low net energy? a. Very little energy goes into making it available.
b. It cannot be used to produce electricity.
c. It needs subsidies to compete in the marketplace.
d. It makes as much high-quality energy available as possible.
e. It is rarely used as a resource in more-developed countries.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.

igneous rocks are formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.  

the composition depends on the source magma. there are almost a thousand types of composition found till now.  

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some scientists like gregory adcock agree with thorne's theory of regional continuity.

others, like chris stringer and ian tattersall, believe thorne's results may be contaminated or misinterpreted.