The threshold on a dose-response curve is the:.
a. point at which the dose of the drug causes maximal response.
b. lowest dose at which there is an observable effect of the drug.
c. safe effective dose of the drug.
d. therapeutic index of the drug.

The correct option is (B)

Explanation:

In toxicology, the dose - response relationship is an important concept.With changes in health and body functions, it correlates exposure.Severe response is seen when the dose is higher.The dose response relationship is based on cell studies, human clinical, and observed data of experimenatl animal.The visual representation of the population's response rate to a range of doses of a substance is a Dose Response curve.

The answer is ozone layer.

Need the answers if its a multiple choice question