Continental air masses are characterized by dry air near the surface while maritime air masses are moist .Polar air masses are characterized by cold air near the surface while tropical air masses are warm or hot. Arctic air masses are extremely cold.
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Anything can be broken down, as long as it is not as small as an atom
Answer:
A neutral particle made of an electron and hole
Explanation:
Exciton
It is the combination of an electron and a hole ( hole refers to the vacancy of an electron ) . And , as both the electron and the hole have the same charge but the polarity is opposite , the combination will lead to a neutral compound , i.e. , Exciton have no charge and so neutral .
It is free to move in the nonmetallic crystal and since it charge less , it is difficult to detect it directly .
