= Solution
TODO: identify the actual plotted branches from an intact source figure. The descriptions below explain how to do so.
In an old <globular cluster>'s <colour-magnitude diagram>, the expected principal sequences are the <main sequence> below the <main-sequence turnoff>, the <subgiant> branch leading to the <red giant branch>, the <horizontal branch> above the <main-sequence turnoff> and extending across colour, and an <Asymptotic giant branch> above the <horizontal branch>, generally near and somewhat blueward of the <red giant branch>. A sufficiently deep diagram can also show a faint blue <white dwarf> cooling sequence; <blue stragglers> may lie above and blueward of the old <main-sequence turnoff>.
The two panels use the <colour index> $B-V$, increasing toward cooler, redder <stars>. On a conventional apparent-<astronomical magnitude> vertical axis, brighter <stars> are higher. These coordinate conventions locate the branches just described.
\b[The supplied PDF does not permit a complete identification of the plotted branches.] Its upper image data are corrupt and render as a grey rectangle, covering the <main-sequence turnoffs> and evolved populations; only lower fragments and $B-V$ axes survive. Thus the list above identifies the relevant <stellar evolution> phases and how to recognize them on an intact plot, rather than claiming that every listed sequence is visibly present in this damaged source. In particular, neither a plotted <white dwarf> sequence nor individual <blue stragglers> can be confirmed from it.
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