Rocks or Dirt. Most of the time geologist will use these to determine factors from the surrounding area such as how old it is, as well as how long its been there.
An advantage of separation of powers includes no one branch being able to control the entire agenda, preventing monarchy.
The National Road. The National Road was the first highway built entirely with federal funds. The road was authorized by Congress in 1806 during the Jefferson Administration. Construction began in Cumberland, Maryland in 1811.