The answer is when GAS IS BURNED because when gas is burned, it cannot return into its previous state. Also, new substances are formed.
Answer:
18 groups are in the modern periodic table
If a hot air balloon has shown rising above the top of a hill, the top of the hill is considered as a reference point.
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Reference Point:</h2>
It is a point that is used to standardize a experiment. The reference point is a constant point.
In the given problem:
- The hot air balloon is rising above the top of the hill. Here, the hill is a standard point that has a fixed (constant) height.
- Some other reference points are the top of the Eifel Tower or a famous shop which a person use to denote a certain distance.
Therefore, "If a hot air balloon has shown rising above the top of a hill" the top of the hill is considered as a reference point.
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5.7 kilometers is equal to 3.5418157957528034 miles
