To determine which metal is NOT used in wood preservatives, we need to consider the common metals utilized in the treatment of wood and their purposes in preservation.
Based on the above analysis, the metal Lead (Pb) is not typically used in wood preservatives due to its toxic nature and environmental impact. Therefore, the correct answer is:
Pb (Lead)
In dose-response curve of chemical substances, there exists a dose below which none of the animal is affected, which is called as: