Answer: biomes

AnswerCrossword Clue
BIOMESEcological complexes
BIOMESSome complex communities
BIOMESEcological units
BIOMESRain forests and grasslands, e.g.
BIOMESEcological communities
BIOMESEcologists' study
BIOMESLarge ecosystems
biomescomplex biotic community characterized by distinctive plant and animal species and maintained under the climatic conditions of the region, esp. such a community that has developed to climax
biomesBIOME, an ecological community