Question: The Oxus cobra contains what kind of ions for their venom to be active? 

Related documents: [0]  [DOC] Ribonuclease V1 (RNase V1) is a ribonuclease enzyme found in the venom of the Caspian cobra ("Naja oxiana"). It cleaves double-stranded RNA in a non-sequence-specific manner, usually requiring a substrate of at least six stacked nucleotides. Like many ribonucleases, the enzyme requires the presence of magnesium ions for activity. [END] 
[1]  [DOC] The Caspian cobra ("Naja oxiana"), also called the Central Asian cobra, Oxus cobra or Russian cobra, a member of the family Elapidae found in Central Asia. [END]  
Answer: magnesium
magnesium