Amphibians Are the "Canary in the Coal Mine" When It

Amphibians are the "canary in the coal mine" when it comes to monitoring threated species.They are especially vulnerable to environmental threats.All of the following observations help us understand their vulnerable status except one.

A) They are both terrestrial and aquatic, so changes in either environment can potentially harm amphibians.
B) They are insensitive to parasites and other infections, so we know that population declines are related to environmental changes promoted by human activities.
C) They have a thin, vascular, moist skin. Pollutants and other agents can easily penetrate the skin and enter their bodies. They are vulnerable to desiccation.
D) They have both aquatic larval stages and adult stages that may be variously susceptible to environmental disturbances.