Q: Given a scientific passage and an answer, generate a question for the given answer.
Passage: Amphibians have permeable skin that easily absorbs substances from the environment. This may explain why they seem to be especially sensitive to pollution. Monitoring the health and survival of amphibians may help people detect pollution early, before other organisms are affected. Answer: amphibians
A:
What group of animals has permeable skin that makes them vulnerable to pollution?