The most important phenomenon of the earth's crust is that it is not stable. It keeps on changing with respect to time called as continental shift. Continental shift squashes and changes a continent in such a way that it is very hard to find out its early history. Continental shift results in earthquakes, volcanoes and tsunamis. The movement of tectonic plates is the main reason for continental shift which leds to the natural calamities such as volcanoes, earthquake and tsunami on the local environment.
Explanation: Elodea or Paramecium live in fresh-water lakes and they are not adaptive to salt-water. Oceans are salty and the cells will lose water due to osmosis and eventually dry up and fall apart.
