Taxonomy is the science of classifying organisms. The system currently used by taxonomists is called the Linnaean taxonomic system, in honor of Swedish biologist Carolus Linnaeus (1707 â 1778). The Linnaean system breaks down organisms into seven major divisions, called taxa (singular: taxon).
When used by the Chinese to protect their land, this section of the wall has had many guards to defend China's capita, Beijing. Made of stone and bricks from the hills, this portion of the Great Wall is 7.8 meters (25.6 ft) high and 5 meters (16.4 ft) wide.
Install retaining wall step-up. 1  When building step-ups, begin the base course at the lowest wall elevation. 2  Dig a base trench that is 24 in. ( 3 600 mm) wide.**. 4  The depth of the trench is determined by allowing for 6 in. ( 5 150 mm) plus an additional 1 in. The depth of the trench is determined by allowing for 6 in. ( 2 150 mm) plus an additional 1 in. ( 3 25mm) for each 1 ft. (300 mm) of wall height for the amount or buried block that is needed. 4  The trench also needs to extend into the slope far enough to bury one full block.**.