Nations Security Council to investigate alleged breaches of the BWC and undertaking to cooperate in carrying out any investigation initiated by the Security Council. Article VII: To assist States which have been exposed to danger as a result of a violation of the BWC. Article X: Undertaking to facilitate, and have the right to participate in, the fullest possible exchange of equipment, materials and information for peaceful purposes. The remaining articles concern the BWC's compatibility with the 1925 Geneva Protocol (Article VIII), negotiations to prohibit chemical weapons (Article IX), amendments (Article XI), Review Conferences (Article XII), duration (Article XIII, 1), withdrawal (Article XIII, 2), joining the convention, depositary governments, and conditions for entry into force (Article XIV, 1–5), and languages (Article XV). Article I: Prohibition of biological weapons Article I is the core of the BWC and requires each state "never in any circumstances to develop, produce, stockpile or otherwise acquire or retain: microbial or other biological agents, or toxins whatever their origin or method of production, of types and in quantities that have no justification for prophylactic, protective or other peaceful purposes; weapons, equipment or means of delivery designed to use such agents or toxins for hostile purposes or in armed conflict." Article I does not prohibit any specific biological agents or toxins as such but rather certain purposes for which they may be employed. This prohibition is known as the general-purpose criterion and is also used in Article II, 1 of the 1993 Chemical Weapons Convention (CWC). The general-purpose criterion covers all hostile uses of biological agents, including those developed in the future, and recognizes that biological agents and toxins are inherently dual use. While these agents may be employed for nefarious ends, they also have several legitimate peaceful purposes, including developing medicines and vaccines to counter natural or deliberate disease outbreaks. Against this background, Article I only considers illegitimate those types and quantities of biological agents or toxins and their means of delivery which cannot be justified by prophylactic, protective, or other peaceful purposes; regardless of whether the agents in question affect humans, animals, or plants. A disadvantage of this intent-based approach is a blurring of the line between defensive and offensive biological weapons research. While it was initially unclear during the early negotiations of the BWC whether viruses would be regulated by it since they lie "at the edge of life"—they possess some but not all