Please answer the following question: Caecilians can be found in moist soil near rivers and streams in tropical regions, and caecilians are primitive amphibians that resemble earthworms. Given these facts, what can be found in moist soil near rivers and streams in tropical regions among the following options: - the sun - bioaerosols - swamp vegetation - gravity - land fish - primitive amphibians - peachleaf willow - Most plants
A:
primitive amphibians