Once upon a time, there was a sky, and the dust in the sky kept condensing, condensing for hundreds

4.6 billion years ago, the Earth was born. Earth's evolution can be broadly divided into three stages.

The solar system 5 billion years ago.

The first stage is the period of formation of the Earth's sphere, which is roughly 4600 to 4200 mA [million years]. When the earth was first born, it was very different from what it is today. Scientists theorize that the Earth began as a red-hot ball of liquid material, mainly magma.

Over time, the temperature of the earth's surface continues to drop, and a solid core gradually forms. The dense material moves towards the center of the earth, and the less dense material (rocks, etc.) floats on the surface of the earth, which forms a earth whose surface is mainly composed of rocks.

The second stage is the Archean, Proterozoic period. Its time limit is between 4200 and 543 MA. The earth is constantly releasing energy outward.

Gases such as water vapor and carbon dioxide released by the continuous eruption of high-temperature magma constitute a very thin early atmosphere --- primitive atmosphere. As the water vapor in the primeval atmosphere continues to increase, more and more water vapor condenses into small water droplets, which then converge into rainwater and fall to the surface. And just like that, the primordial ocean was formed.

The third stage is the Phanerozoic period, which lasts from 543 mA to the present. The duration of the Phanerozoic is relatively short, but during this period, the organisms and their flourishing, the geological evolution is very rapid, the geological processes are rich and colorful, and the geological bodies are all over the world, widely preserved, which can be observed and studied very well, and are the main research objects of geological science, and the basic theories and basic knowledge of geology have been established.

In order to prove the origin of life and the earth, various hypotheses have been proposed to explain the birth of life through experiments and speculation. In 1953, Stanley, a young American scholar, used a closed device filled with methane (CH4), ammonia (NH3), hydrogen (H2) and water (H2O) in the laboratory to simulate the environmental conditions of the primitive earth by discharging and heating, and synthesized some amino acids, organic acids and urea and other substances, which caused a sensation in the scientific community. The results of this experiment show even more convincingly that the early earth was fully capable of giving birth to living organisms, and that primitive living matter could be produced under natural conditions without life.

Some organic substances in the primitive ocean, after long-term and complex chemical changes, gradually formed larger and more complex molecules, until the basic substances that make up living organisms--- proteins, and nucleic acids and other macromolecular substances as genetic material. Under certain conditions, substances such as proteins and nucleic acids are concentrated, condensed, etc., forming a system composed of a variety of molecules, with a membrane on the outside, separated from seawater, and undergoing long and complex changes in seawater, and finally forming primitive life.

In short, the evolution of the earth has led to the birth of life on the earth.

The earth is a part of the sun, and the earth seems to fly out of the sun, which is also a fragment of the sun

No, it turns out that in the current location of the solar system, there is a solar star composed of gas, rocks, ice, etc. About 4.6 billion years ago, some rocky gases began to diverge from the solar nebula, and the temperature was lower, and the current Earth was formed after asteroid impact and geological movements.

After so many years, out of you.

(1) Serious soil erosion;Water scarcity;Water pollution is expanding;Air pollution is severe;Noise pollution is gradually expanding;Household garbage and white pollution are spreading, etc. Just write two aspects).

2) It threatens the ecological balance, endangers human health, and directly restricts the sustainable development of China's economy and society.

3) Implement sustainable development strategies, control population growth, conserve resources, and protect the environment.

4) Afforestation;No or less disposable chopsticks;Use less plastic bags;Save and ** waste paper;Save electricity and turn off the lightsSave water and turn off the faucet;Watering the flowers with water that has been washed with rice, etc. (Just make sense).

5) For example: To be kind to nature is to be kind to human beings;Protecting the environment for the benefit of future generations;The environment is the foundation of human existence;Improve the ecological environment and build a better future;Implement sustainable development and build a better home together;Not only gold and silver, but also green waters and green mountains. (Be catchy, concise and powerful, motivating and appealing).

The earth we live on is a beautiful blue planet from space, and it looks more like a "water ball" According to people's calculations, 71% of the earth's surface is ocean, while only 29% of the land area Therefore, option B is in line with the topic; Options a, c, and d are not in line with the topic

Therefore, b