The figure is a simple litholog with the ranges of two bivalve species, A and B, marked by their first occurrence (FO) and last occurrence (LO) levels. The question asks which biozone types such a diagram can show.
Concurrent range zone: defined as the interval where the ranges of two chosen taxa overlap. Since both species' full ranges are drawn, the overlap between them can be read straight off the figure. This one fits.
Interval zone: defined as the strata between any two marked bio-events, such as the FO of A and the FO of B. The figure gives exactly these datum points, so an interval zone can also be read off it. This one fits too.
Assemblage zone: needs a group of several taxa found together as a characteristic association, not just two range bars, so this figure with only two species does not show it.
Acme zone: needs abundance counts through the section to mark a peak in numbers of one taxon, and the figure carries no abundance information at all, only presence and absence, so this does not fit either.
Only the first two options can be read directly from a simple two-species range chart with FO and LO marked.
Let's summarize:
Concurrent range zone comes from the overlap of two taxa's ranges.
Interval zone comes from any two marked datum levels, overlap not required.
Assemblage and acme zones need more information, a taxon group or abundance data, than simple range bars give.
So the figure depicts a concurrent range zone and an interval zone.
