Final answer:
An expedition might lose hope due to various challenges such as lack of proper preparation, harsh environmental conditions, or they run out of resources. Their despair is justified when survival or success chances are particularly low or nil.
Step-by-step explanation:
The failure of an expedition can be due to numerous factors such as lack of proper planning, challenging natural conditions, insufficient resources, or unforeseen disasters. An expedition group might lose hope when the collective belief in their success wanes, often a result of such challenges.
Regarding the justification for their despair, when the odds are overwhelmingly against success and survival chances are shrinking, their despair could be seen as justified. For example, if an expedition was stranded in a blizzard with dwindling supplies, then despair would be a natural reaction to such a dire situation.
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