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 mineral nutrient needed by humans in very small amounts. Chromium appears to be important in the metabolism of fats, proteins, and carbohydrates, and the regulation of blood sugar. In order for glucose to gain entry into cells where it can be used for energy, insulin must function properly.