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 theory of plate tectonics is a relatively new scientific concept. While its forerunnerâthe theory of. continental driftâhad its inception as early as the late 16th century, plate tectonics only emerged and. matured as a widely accepted theory since the 1960s (see This Dynamic Earth booklet).
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