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Question
It is desirable that the standards of units be easily available, invariable, indestructible and easily reproducible. If we use foot of a person as a standard unit of length, which of the above features are present and which are not?
Solution
If we use a person's foot as a standard unit of length, features that will not be present are variability, destructibility and reproducible nature. The feature that will be present is the availability of a person's foot to measure any length.
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