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it explains what your looking for
Answer: The Earth is a closed system for matter
That is a list of all basic elemental materials on our planet. Because of gravity, matter (comprising all solids, liquids and gases) does not leave the system.
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Answer:
D
Explanation:
If NASA had constructed a Space Shuttle without knowing if it would be safe for its passengers, there could be many casualties. So they would test it beforehand using a model, to make sure that it will be safe and sturdy for when they build it.
