(2Z,6Z)-farnesyl diphosphate synthase activity https://github.com/geneontology/go-ontology/issues/20661 https://github.com/geneontology/go-ontology/issues/28526 GO:0102192 MetaCyc:RXN-10481 Catalysis of the reaction: 2 isopentenyl diphosphate + dimethylallyl diphosphate = (2Z,6Z)-farnesyl diphosphate + 2 diphosphate. EC:2.5.1.92 RHEA:27810 zFPS activity 2-cis,6-cis-farnesyl pyrophosphate synthase activity cis,cis-farnesyl diphosphate synthase activity molecular_function Z,Z-FPP synthase activity GO:0102059 neryl-diphosphate:isopentenyl-diphosphate cistransferase activity Z,Z-farnesyl pyrophosphate synthase activity prenyl diphosphate synthase activity