(a)The Haber process takes nitrogen gas from air and combines it with water molecule to form ammonia gas.(b)The Haber process takes nitrogen gas from air and combines it with molecular Oxygen gas to form ammonia gas.(c) The Haber process takes nitrogen dioxide gas from air and combines it with molecular hydrogen gas to form ammonia gas.(d) The Haber process takes nitrogen gas from air and combines it with molecular hydrogen gas to form ammonia gas.