composed primarily of material entity macromolecule environmental material portion of environmental material A material entity which other material entities in an environmental system are primarily or partially composed of. Everything under this parent must be a mass noun (i.e. not countable). All subclasses are to be understood as being composed primarily of the named entity, rather than restricted to that entity. For example, "ENVO:water" is to be understood as "environmental material composed primarly of some CHEBI:water". Instances of this class are portions of environmental materials, such as seawater in bucket, a water parcel in the photic zone of a lake, or the concrete that composes a building part. Instances of these portions may have fiat or non-fiat boundaries. For example, a water parcel has not physical boundaries, while the seawater in a bucket is bounded by the internal surfaces of the bucket.