1 For subsidence caused by sudden collapse of the ground to form sinkholes, several measures can be taken. 2  First, geologists can make maps of areas known to be underlain by rocks like limestone, gypsum, or salt, that are susceptible to dissolution by fluids.
The Navajos used bows and arrows, spears, clubs, tomahawks, knives and sticks among their tools and weapons. Beyond these, they also used bolas and... The Navajos used bows and arrows, spears, clubs, tomahawks, knives and sticks among their tools and weapons. Beyond these, they also used bolas and blowguns. The Navajos employed the use of several tools and weapons:Bows and arrows were used by Native Americans to defend themselves, and sometimes for fishing. They also used them for hunting animals like bison.When fighting against European explorers, Native Americans used spears.
Another tool known to the ancient Maya was a sort of hatchet or ax. The handle was made of wood, and could be 12 to 16 inches long. The head was a celt made of chert. The Maya stuck the head into the handle, near one end. This type of ax/hatchet, according to The Ancient Maya: New Perspectives, was the tool the ancient Maya used the most for farming. Farming and Gender As for gender, there's a theory that farming was men's work -- and women did different jobs at the house.