1 They could be symptoms of cancer of the lung, head, and neck. 2  Anyone with a cough that lasts more than a month or with blood in the mucus that is coughed up should see a doctor. 3  A change in bowel habits. 4  Most changes in bowel habits are related to your diet and fluid intake.
The theoretical model builds on the concept of continental drift developed during the first few decades of the 20th century. The geoscientific community accepted plate-tectonic theory after seafloor spreading was validated in the late 1950s and early 1960s. The lithosphere, which is the rigid outermost shell of a planet (the crust and upper mantle), is broken up into tectonic plates.
This theory has been supported since then by the advance of technologies that allow scientists to actually measure the movement of the plates in centimeters per year. Plate tectonics is the current accepted theory that describes how the face of the earth can change over time. Learning Outcomes. After watching this lesson, you should be able to: Describe the plate tectonics theory ; Explain what causes plates to move ; Identify the lithosphere, asthenosphere, mantle, and core