Answer:
On their mode of formation
Explanation:
The classification of rocks into three major categories is strictly based on their mode of formation.
Rocks are naturally formed aggregates of minerals. Based on mode of formation, they can be classified into;
- Igneous rocks: these rocks are formed by the cooling and solidification of molten magma.
- Sedimentary rocks are formed by the compaction and lithification of sediment.
- Metamorphic rocks: these are changed rocks that have been formed by subjecting rocks to pressure and temperature conditions which causes an alteration of their minerology.
The southern part of the United States is heavily influenced by the sea/ocean and the wind patters that occur because of it. The warm waters that surround the region are making it more stable temperature-wise and the weather is warm and wet for big portions of the year. The precipitation is high as well. But this also brings in problems in the shape of the hurricanes, tornadoes, intense big rainstorms, and floods.
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The build-up of three oxygen created our ozone layer around two billion years ago.
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- The ozone layer is a part of the stratosphere which is located right after the troposphere in the atmosphere of the Earth.
- The ozone gas is made up of the abundance of three oxygen molecules combining with the ultraviolet radiation emitted by the Sun.
- The development of the ozone layer happened around two billion years ago when the oxygen concentration levels on the planet began to rise slowly and gradually.