Answer the following question given this paragraph: 

Why are so many amphibian species threatened by extinction, and why should you care? The second question is easy. Amphibians control pests, may be a source of new medicines, and help feed many other animals. The nature of amphibian skin may help explain why so many amphibian species are at risk. Their skin easily absorbs substances from the environment, such as pollutants in water or air. Therefore, they may suffer from poor environmental quality before other animals do. As such, they may provide an early-warning system of environmental damage.


Q: Which part of the body of amphibians, easily absorbs substances from the environment?

 Choices:

- liver

- scales

- Eyes

- skin

A:
skin
