Every opening in the roof, ceiling or walls must have a filter or screen at the boundary so that animals, invertebrates included, cannot get in or out. The filter or screen material must be mechanically strong enough for any airflow load, survive regular cleaning without damage, and resist both corrosion and animals, invertebrates included, breaking through.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.