Answer & Explanation:
Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter. They include reactivity, flammability, and the ability to rust. Reactivity is the ability of matter to react chemically with other substances.
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Answer: The right answer is Cave-ins.
Explanation: Excavations and trenches are basically the man-made cuts inside the Earth's surface. These are made for multiple purposes such as mining or tunneling. One of the obvious risk while working in such excavations and trenches is cave-ins. It is basically collapse of that excavation or Trench. The roof of the mine collapses and people working under it get buried inside those excavations in trenches.
