Final answer:
The collapse of the Russian army during World War I was primarily due to a shortage of food, supplies, and ammunition.
Step-by-step explanation:
The best explanation for the collapse of the Russian army during World War I was that the country was running low on food, supplies, and ammunition.
The Russian army faced severe logistical issues, with inadequate supply lines and a lack of resources. This led to soldiers being poorly equipped and fed, which severely impacted their combat effectiveness.
Additionally, the country was also grappling with internal instability and unrest, further undermining the army's ability to effectively fight the war.
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