True or false. an ecoregion is defined as a large area of land or water that contains a geographically distinct assemblage of natural communities.

The statement is true. An ecoregion is defined as a large area of land or water that contains a geographically distinct assemblage of natural communities.

Explanation:

Ecoregions are relatively large areas of land or water that are more or less homogeneous geographically and ecologically. The biodiversity of flora, fauna and ecosystems that characterize an ecoregion tend to deviate from that of other ecoregions.  

The World Wildlife Fund (WWF), which described the ecoregions, distinguishes 867 terrestrial, around 450 freshwater and 232 marine ecoregions.

81 is a composite number.