The outside of electrical wires often have a layer of insulation to protect the user from being shocked. This protective layer is often made from

Most electrical wire is covered in a rubber or plastic coating called insulation.

Explanation:

Wires used in homes are usually covered with materials like plastic or rubber, because plastic and rubber are bad conductors of electricity and do not allow current to flow. This prevents us from getting a shock due to a short circuit.

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.