<u>Answer and Explanation:</u>
The mechanism which is responsible for moving the plates that bring change in the position of the continents is the convection in the asthenosphere.
Henry Hess, a geologist and an American Navy officer in the World War II, discovered that the sea floor and the the Mid Atlantic Ridge is spreading which helped the the scientists in studying and understanding the mechanism of how the plates move.
PRECIPITATION,TEMPERATURE, VEGETATION
Got this from google, scientists count a species population by first knowing the population in a certain area or small geographical sample location then multiply the result by the total area.
All of the states of the USA are north of the equator.
So are all the states of Mexico.