Why there is no area 0(backbone area) in this topology?

[George-Sl]

Why there is no area 0(backbone area) in this topology while there are two ospf areas 24 and 34?

Thanks

[e.ciollaro]

Hard to say why there is no Area 0, OSPF permits two areas without a backbone Area, but traffic can't be router between the two areas. May be in tha scenario routing is through OSPF to EIGRP redistribution.