A desert is a beautiful land of silence and space. The sun shines, the wind blows, and time and space
1
endless. Nothing is soft. The sand and rocks are
2
, and many of the plants even have hard needles instead of leaves.
The size and location of the world"s deserts are always
3
. Over millions of years, as climates change and mountains rise, new dry and wet areas
4
But within the last 100 years, deserts have been
5
at a frightening speed. This is partly because of natural changes, but the greatest desert makers are humans
In the nineteenth century some of the people living in the English colonies in Australia
6
some rabbits from England. Today there are millions of rabbits
7
eat every plant in sight. The great desert that covers the center of Australia is growing.
The land in the southwestern United States is rich. Large farms grow crops that
8
a lot of water, but there is only a little rainfall. The level of the underground water table is
9
every year.
In developing countries, 90 percent of the people
10
wood for cooking and heating. They cut down trees
11
firewood. But a tree cools the land under it and keeps the sun off smaller plants.
12
the leaves fall, they make the land richer. When the trees are gone, the smaller plants die, and there is nothing but sand.
13
people must have firewood, animals, and crops in order to live.
Humans can make deserts, but humans can also
14
their growth. Algeria is planting a green wall of trees across the edge of the Sahara to stop the desert sand. Can people stop the growth of the worlds deserts and save the land that is so essential
15
life No one has the answer.