More than 60 million years
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It is important for the United States to build canals (wide canals) because the country is visited multiple times by hurricanes annually. Hurricanes are accompanied by heavy rainfalls and if left unchecked, causes flooding. The function of canals is to diffuse accumulated rainwater and direct it to greater bodies of water.
Answer:
extrusive rocks.
Explanation:
When an igneous rock contains large crystals of minerals surrounded by the fine grained or glassy material (set in a matrix of glassy part).The texture is known as Porphyritic texture and the large crystals are known as Phenocrystals and the fine grained or glassy part is called as Ground mass.
When this Porphyritic texture showing igneous rocks are known as Porphyrites. The texture is largely found in volcanic and hypabassal rocks so these rocks are the extrusive rocks.
Answer: Ozone is considered as chief polluting gas.
Explanation:
The ozone is a ground level pollutant. It is a colorless gas. It causes irritation in the eyes and respiratory tract. It is one of the components of smog as it causes pollution in the atmosphere. It is produced by the two primary pollutants that are nitrogen oxides and volatile organic compounds when they react with the sunlight. The ozone makes the air irrespirable. It is the main cause of throat irritation, labored breath, pain in chest and also responsible for respiratory diseases. It reduces the body's ability against infection. The ozone depleting substances like aerosol, chlorofluorocarbon are widening the ozone depleting zone as halides present in these substances react with the ozone causing depletion. This allows the entry of harmful ultraviolet radiation penetrating the atmospheric layers.
