Final answer:
The proper plural spelling of the term phalanx is phalanges.
Step-by-step explanation:
The proper plural spelling of the term phalanx is phalanges.
In English, when a word ending in -x changes to its plural form, we usually replace the -x with -ges.
For example, other words that follow this pattern include index (plural: indices), vortex (plural: vortices), and appendix (plural: appendices).
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