witch o2 senser is bank 1 the one closest to the motor or the on e at the cat on 2005 Mazda RX-8

the code that came up saID O2 SENSER BANK 1

Asked by for the 2005 Mazda RX-8
Hello yes the one closest to the engine is bank 1 sensor 1 you might want to make sure the oxygen sensor is the problem and not a vac.leak.HAVE A BLESS DAY from DR. RECO.