Steroids and other medications. Long-term use of oral or injected corticosteroid medications, such as prednisone and cortisone, interferes with the bone-rebuilding process. Osteoporosis has also been associated with medications used to combat or prevent: Seizures; Gastric reflux; Cancer; Transplant rejection; Medical conditions
The main functions of using a compass are: 1  tell which direction you are traveling - your heading. 2  tell which direction an object is from you - its bearing. 3  keep you following a straight line of travel. 4  orient a map - aligning a map with the actual land.  triangulation - determining your location with a map.
A compass works by aligning its magnetic needle with the Earth's magnetic field, which is created by the iron core deep inside the planet. A compass is exactly accurate since the Earth's magnetic north differs slightly from Earth's true north.