Assertion: virus | /r/HasAspect | outer envelope
Facets:
Source sentences:
text: Some viruses also have an outer envelope made of lipids, which are fatty organic molecules.
text: A virus consists of a single- or double-stranded nucleic acid and at least one protein surrounded by a protein shell, called a capsid; some viruses also have an outer envelope composed of fatty materials (lipids) and proteins.