Farm system boundaries: Discussion of system boundaries in Chapter 3 mainly relates to farms of this type. Briefly, boundaries of Type 2 farm systems (and of Types 1, 3 and 4) segregate them distinctly from the external world, but the boundaries between individual farms are relatively weak.
What is Chromium? Chromium is a steel-gray lustrous metal that is important as an additive in the manufacture of steel alloys (chrome steel, chrome-nickel steel, stainless steel) and greatly increases the durability and resistance of these metals; hence its use in metal prosthetic implants.
Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard and brittle metal[4] which takes a high polish, resists tarnishing, and has a high melting point. The name of the element is derived from the Greek word ÏÏá¿¶Î¼Î±, chrÅma, meaning color,[5] because many chromium compounds are intensely colored.