The spiral usually begins with an increase in demand. The direct effect of this increase is that the producers (of commodities) raise prices to continue to make a profit. It usually begins with a rise in production costs.
The concept would be crystallization. As magma cools inside or outside of the earth it crystallizes into an igneous rock. Intrusive (formed inside crust) igneous rocks are typically more course grained and contain many different noticeable minerals (for example, granite). Extrusive (formed outside) igneous rocks are typically more porous and are more fine grained then intrusive rocks (example, obsidian).
answer for this question is A
No 2 people in the world are "exactly alike", so the odds would be 0% chance. Twins, might be closer in alike-ness, but they still aren't "exactly alike". Hope this answered your question.