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).
The geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s. The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates.On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates.he geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s. The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates.