atrial fibrillation. n. Abbr. AF. Fibrillation in which the normal rhythmical contractions of the cardiac atria are replaced by rapid irregular twitchings of the muscular wall that cause the ventricles to respond irregularly. Also called a-fib, auricular fibrillation.
continental=on land. here is a good example of plate tectonics, i just had to explain all that stuff. Subduction is when converging plates come together. they make a trench by one plate sliding under the other and into the mantle.
Plate Movements In the 1960s, scientists developed a newtheory that combined continental drift and seafloor spreading.According to the theory of plate tectonics, Earthâs crust and partof the upper mantle are broken into sections. These sections,called plates, move on a plasticlike layer of the mantle.ECTION 3 Theory of Plate Tectonics 195 SECTION 3 Theory of Plate Tectonics 195 Causes of Plate Tectonics Many new discoveries have been made about Earthâs crustsince Wegenerâs day, but one question still remains.