Reliable because it's not always sunny
Answer:
Food and security.
Explanation:
The presidios faced many challenges such as food and security of its people and struggle to maintain their control from the natives people and save themselves from native people that lives around them because the Spanish comes and captured their lands. Spanish soldier defend the newly captured territories and take on such a difficult job for their country's welfare, prosperity and for expanding influence of their country.
If we are talking about the second world war, then then answer would be that the Chinese kept the Japanese busy fighting them, and in turn, about 800,000 of their troops. This gave the Americans, who were the main force against the Japanese during this time, a little breathing room with which to continue military operations.
Hope this answered your question.
Answer:
The US economy collapsed.
Explanation: