Precision can be defined as

the exact center of a data set.
reproducible of a measured value.
correlation between two variables that are measured in a data set.
agreement between a measured value and an accepted value.

Reproducible of a measured value.

Explanation:

Precision refers to how close two values that were measured are. It indicates the degree in which different measurements reproduce the same results.  According to this, the answer is that precision can be defined as reproducible of a measured value.

there is none because earth is stationary and flat.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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