How many oxygen sensors does this vehicle have?

How many oxygen sensors do I have? I am asking because in the past I have seen both cars with one oxygen sensor and with two oxygen sensors and in this car the intake manifold plenum is preventing view of the exhaust manifold so I can't see the oxygen sensor or sensors, and what happens if the oxygen sensor goes bad? Does it prevent the car from starting up or does the engine just run rough and poorly with the check engine light illuminated? I can live with engine performance problems because I do three-month interval bulk synthetic oil changes at Walmart and so the engine won't seize up it will just perform poorly, but I can't live with a crank but no start condition and that condition damages both the battery and starter motor?