'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.
At first, they were obeying King George but later on, they became rebellious and many events happened that led to the revolutionary war. For example, the Boston tea party, the Boston Masacare, and many others.
Answer:
The Crust is mostly made up of loose materials.
The Mantle is made of up of a thick solid rock substance.
The Outer Core is made of super heated liquid molten lava.
The Inner Core is believed to be solid ball of mostly iron, and nickel.
Explanation:
The earth tilts for different times of the year. During the summer Alaska is a lot closer to the sun than florida.
