Final answer:
The amount of a substance that can be safely exposed to without harm is the Threshold level. This concept is significant when evaluating the safety and toxicity of chemicals and establishing permissible exposure limits.
Step-by-step explanation:
The amount of a substance to which you can be exposed without suffering injury is known as b) Threshold level. This term refers to the point below which a substance does not appear to cause any adverse health effects. Every chemical can be toxic in large enough quantities; toxicologists use the concept of the threshold level to assess the risk associated with exposure to chemicals. The concept is key when discussing dose-response relationships, lethal doses (LD-50), and safety guidelines or standards.
For instance, chemicals must be tested to determine their LD-50 values, which indicates the dose that is lethal to 50% of a test population, helping to establish the safe exposure limits for humans. Additionally, regulatory bodies set standards, referred to as permissible levels or primary standards, to prevent both health impacts and environmental damage based on this kind of toxicological data.