'Climatic variations' and 'Human activities' can be regarded as the two main causes of desertification. removal of the natural vegetation cover（by taking too much fuel wood）, agricultural activities in the vulnerable ecosystems of arid and semi-arid areas, which are thus strained beyond their capacity.
PRECIPITATION,TEMPERATURE, VEGETATION
Fossils are the remains of plants and animals that have been preserved for millennia in stones under the Earth's surface. They contain the long chapters of the history of our Earth. Fossils tell us what the earth looked like many millions of years ago, what kind of animals and plants lived on its surface and how it was changing. Fossils show us a history of over a billion years old.
From the fossil from a dry, mountainous area we can conclude that the area was once underwater and over time the soil has risen as result of continental drift and uplift. So, a mountain was once the bottom of a prehistoric ocean or sea.
That would be the Himalayas and have the highest mountain range in the world.
1.Google Earth
2.united parcel service
3.housing
