nucleus. remember it as the brain of the cell
Stable elements are those which have atleast one isotope with no tendency to "decay", i.e., change into anotherelement.
Answer:
- the discovery of the Pangaea Theory.
In 1912 Alfred Wegener (1880-1930) proposed that the continents were once compressed into a single protocontinent which he called Pangaea (meaning "all lands"), and over time they have drifted apart into their current distribution.
The east coast of South America and the west coast of Africa seem to fit together like pieces of a jigsaw puzzle, and Wegener discovered their rock layers “fit” just as clearly. South America and Africa were not the only continents with similar geology. Most all of the other continents fit together too.
The reticular activating system's main function is regulating arousal and sleep−wake transitions
