Question

sort the words according to the meanings of their shared roots. populous unfortified overpopulation repopulated popularity refortify people strength

Explanation:

The root - "popul" is related to people, so words like populous, overpopulation, repopulated, popularity belong to the "people" category. The root - "fort" is related to strength, so unfortified and refortify belong to the "strength" category.

Answer:

People: populous, overpopulation, repopulated, popularity
Strength: unfortified, refortify