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What is air 2
Reading 1
Scientists believe that the earth is four and a half billion years old. Our atmosphere, the air, was very different when the earth was new. Many believe that it was formedfrom escaped gases from volcanoes, coming from deep within the earth. It was dangerous to breathe! For the first billion years, the atmosphere was probably mainly nitrogen, hydrogen, carbon dioxide,and water vapor. It contained no oxygen;
within the oceans, some of the organisms developed an ability to use the sun´s energy to take the carbon dioxide and water .This amazing process is calledphotosynthesis
The earth´s atmosphere is a constantly moving body of gases that encircle our planet. It consists of about 78 percent nitrogen; about 21percent oxygen, and carries along with it watervapor, clouds, dust, smoke, soot. The remaining one-percents contain all the other gases including carbon monoxide, carbon dioxide, ozone, methane, and ammonia that contribute to air pollution. theatmosphere extends about 600 miles into space.
Although only the air in the troposphere is suitable for breathing, the upper atmospheric layers are also important for life on earth. the stratosphere.dangerous ultraviolet rays from the sun. This filtering helps control the earth´s temperature

¿Qué es el aire 2
Lectura 1
Los científicos creen que la tierra es de cuatro y medio millones de años.Nuestra atmósfera, el aire, era muy diferente cuando la tierra era nueva. Muchos creen que se formó a partir de los gases fugados de los volcanes, que viene de las profundidades de la tierra. Erapeligroso respirar! Para los primeros mil millones de años, la atmósfera era probablemente principalmente nitrógeno, hidrógeno, dióxido de carbono y vapor de agua. No contenía oxígeno
dentro de losocéanos, algunos de los organismos desarrollaron la capacidad de utilizar la energía del sol para tomar el dióxido de carbono y agua, Este proceso se llama fotosíntesis increíble La atmósfera de la...