Complex sentence: Cobra is the common name of various elapid snakes, most of which belonging to the genus "Naja", all of which are venomous and many of which are capable of rearing upwards and producing a hood when threatened.
Split into simpler sentences: Cobra is the common name of various elapid snakes, most of which belonging to the genus "Naja". All of the known cobras are venomous and many of which are capable of rearing upwards and producing a hood when threatened.