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 member of group 6, of the transition metals. Chromium(0) has an electronic configuration of [Ar]3d 5 4s 1, owing to the lower energy of the high spin configuration. Chromium exhibits a wide range of oxidation states, with +3 the most stable; the +3 and +6 states are the most common in chromium compounds, while +1, +4 and +5 are rare.