A large study in 2008 by Dunn 'et al.' strongly supported the ecdysozoa as a natural grouping.

An examination of data from 1139 15-month-olds showed that variation was continuous rather than falling into natural groupings.

This produces natural groupings without requiring any inference about soil genesis.

This clade is probably not a natural grouping and is likely to be revised in the future.

Today, the animals live in natural groupings rather than as individuals.

Defining the limits so that Arius can form a natural grouping has always been a problem.

Or has the idea of natural racial groupings always existed?

The order or "natural" grouping of questions is often relevant.

If this was a natural grouping, it seemed unlikely that it could be an old one.

Trees and shrubs were planted in "natural groupings" on the lawn.