QUESTION: Fix punctuation: But before dealing with this in greater detail I must return to the part of my letter devoted to a factor of prime importance namely the imperialist world war
ANS: But before dealing with this in greater detail, I must return to the part of my letter devoted to a factor of prime importance, namely, the imperialist world war.
QUES: In fact it is more lucrative casino bonuses you can claim here as a new player and the casino offers up 10000

correct the punctuation.

CORRECTED: In fact it is more lucrative casino bonuses you can claim here as a new player, and the casino offers up $ 10.000.
Question: What this means for example is that if someone finds the computer that Alice in class 6c left on the bus it will be easy for the school to recover it
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Answer: What this means, for example, is that if someone finds the computer that Alice in class 6c left on the bus, it will be easy for the school to recover it.
Brachiation Ladder 250 cm code 282

Can you repeat this sentence, but add in punctuation?
Brachiation Ladder, 250 cm, code 282
input: A reader wrote what a friend told her a medium had told him The people on earth would be transported to a very large planet that is big enough to hold the population of the earth
fixed: A reader wrote what a friend told her a medium had told him: The people on earth would be transported to a very large planet that is big enough to hold the population of the earth.
With a total capacity of five megawatts the new power plant will supply half the power needed by Cobija the largest city in Pando province

Can you repeat this sentence, but add in punctuation?
With a total capacity of five megawatts, the new power plant will supply half the power needed by Cobija, the largest city in Pando province.