There are many types of mountains on Earth. Some of them are covered with thick green forests while the tops of others are covered with ice and snow. It is very cold there. There are some dry and hot mountains. Many rivers begin high in the mountains. This is an amazing part of nature. In fact, the mountains appear even today. These are parts of the crust that change shape due to volcanic eruptions, earthquakes or tectonic plate movements deep underground. Life in the mountains can be pretty hard, but people live there. The main point is there are no good roads, shops or hospitals. People have to ride animals or on foot, as cars cannot drive everywhere. At high altitude, the air is thin, and you have to get used to it. Are there mountains in the area where you live?
In many ways, the planet Earth resembles an orange. They have a similar shape. The planet also, like this fruit, has its own skin — the earth's crust. There are holes in the earth's crust — volcanoes. When they erupt, stone, ash, and hot lava fly out. Thanks to volcanoes, new islands sometimes arise at the planet. Two thirds of the land are covered by water. Basically it is the salty water of the oceans and seas that cannot be drunk. But there are also rivers with fresh water, thanks to which trees grow and animals survive. Rivers usually start in the mountains. They gather from snow or rain and begin to flow below. Rivers form waterfalls. The largest and most beautiful of them are favorite places of tourists even today. Fresh water is very important for life on the planet.
