First blank : Wealth and technology together can certainly be considered to do some good for a region. Hence, the first blank gives an idea that the northern hemisphere had an upper strategic hand which closely matches to the option choice "advantage".

Second blank : It is mentioned that they had more sophisticate weaponry compared to the southern hemisphere. From this sentence and the previous sentence which mentions the north had an advantage, it can be inferred they were more developed than the south. In other words, the south lacked advanced weaponry and had basic weaponry. Hence, the word that fits in second blank is "rudimentary".

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