Fact 1: Amphibians have permeable skin that easily absorbs substances from the environment.

Fact 2: Amphibian skin lacks hair or scales.

Given the two facts above, answer the question "What do amphibians lack?" with the following options: 
- brain
 - fat
 - hair
 - power
 - oxygen
 - lungs
 - nectar
 - skin


 

   hair      