Answer:
The answer would be Point of Reference.
In order to determine, whether an object has moved or not, a point of reference is required. The reference point is required to the measure the movement of the object, without a reference point the distance or displacement cannot be obtained. Hence, a reference point is very required to determine, whether the object has moved or not.
(Hope this helps) Sky
The finagling in the hole
In order to solve this question, we must apply the conservation of mass. The total number of nucleons (upper number) and protons (lower number) must be equal before and after the decay. The new nucleon number is
218 - 4
= 214
And new proton number is
84 - 2
= 82
Next, we must identify which element has the proton number 82. That would be lead, Pb.
Therefore, the answer is
5. ²¹⁴Pb₈₂
Probably ion with a positive 1 charge.
Explained briefly