2. instrumental music

3. Wrong woodwind instrument

4. Tang Dynasty

5. Anhui

6. Beethoven

7. Mongolia, Kazakhstan, Kyrgyzstan, Afghanistan and Tajikistan

This is because ancient animals and plants were buried underground after crustal movement and formed after several years of chemical changes.

During the geological and historical period millions of years ago, due to the very suitable climatic conditions, lush and tall plants grew on the ground, and a large number of plants also grew in coastal and inland swamp areas. At that time, the rainfall was quite abundant. When natural disasters such as the once-in-a-century flood or tsunami come, grasslands and large forests will be flooded, and plants, large and small, there will be uprooted and floating on the water. The soil at the roots of plants will also be washed away. These trees and grass with roots and branches will also climb and entangle each other and go down the river. Once they are washed to shallows and bays, they will run aground, where they will settle down and screen out all the floating objects like a sieve. Soon, a barrier will be formed here, and this place will also be the accumulation place of plant remains (and many animal remains) in the next flood. When the flood recedes, a winding pile of plant debris will form here. After long-term geological changes, this pile of plant debris will gradually be buried underground and eventually evolve into today's coal mine.

Then some people may ask, why didn't this happen when China was hit by a rare flood in 1998? I think that's because the current forest coverage rate in China is very low. Most places with forests are at high altitudes, and the plains are full of grain fields, almost to the point where there is no forest to flood, but some farmland shelterbelts are flooded, and the trees in farmland shelterbelts are rare, and the roots of trees are well developed, so they can firmly grasp the land, and short-term soaking and impact will not cause much damage. The trees in the forest are different. Many trees live together. In order to absorb the energy of the sun, they grow up desperately, and their roots are underdeveloped. Once a tree is uprooted by the flood, it will be destroyed by the flood, just like putting a raft down the river, unstoppable, and finally all piled up in one place.

In addition, due to the enhancement of human understanding of nature, the ability to resist sudden natural disasters has been continuously improved. Building water conservancy projects, building strong dams and strengthening river embankments have greatly slowed down the impact of fierce floods, and the phenomenon of flooding has become less, even obediently obeying the call of human beings, turning fierce floods into electric energy, kinetic energy and heat energy, benefiting mankind and serving human society.

Not only floods have the ability to carry animals and plants, but tides, typhoons and tsunamis also have this ability. Tsunamis caused by earthquakes, volcanic eruptions and other factors can make the waves rise by more than 30 to 40 meters, and instantly wipe out the animals and plants on an island; Plunder all living things near the coastline.

Moreover, the material on the surface cannot wait for the earth to sink forever, and the material on the surface is constantly circulating. Therefore, whether the "flood theory" makes coal so concentrated and high-quality still makes sense, which is convincing and can be convincing.

The material on the earth's surface can't wait for the earth to sink forever. The material on the earth's surface is constantly circulating. Therefore, whether the "flood theory" makes coal so concentrated and high-quality still makes sense, which is convincing and can be convincing.

It is an irrefutable fact that coal is indeed formed by the systematic evolution of plant residues. As long as you look at the coal carefully, you can see the traces of leaves and roots of plants. If you slice coal and observe it under a microscope, you can find a very clear plant tissue structure. Sometimes things like tree trunks are still preserved in coal seams, and some coal seams are still wrapped with complete insect fossils. Why it is so concentrated and of such high quality is worth discussing.

Due to the deposition of a large number of ancient plants, they were buried deep underground, subjected to high pressure and high temperature, and turned into coal after hundreds of millions of years.

Coal mines, like other mines, are layered, not everywhere. If it is accumulated by surface plants, it will not be so concentrated, and it should be everywhere, so I think what the book says is wrong. Carbon exists in the earth. Most of the carbon on the surface exists in the form of compounds, while the carbon in the center of the earth exists in the form of simple substances. When the carbon in the center of the earth is sprayed to the surface, it is partly diamond, partly graphite and mostly coal (different substances are formed under different conditions), which is the same as the origin of most other mines.

Plants are pressed underground and will form coal under the condition of long-term hypoxia and high pressure.

In Carboniferous, the plants on the earth flourished, which provided a strong material basis for the formation of coal, and the subsequent orogeny provided external conditions for the formation of coal. Many years later, there was coal.