What is a Command Economy?

A planned economy is a type of economic system where investment, production and the allocation of capital goods takes place according to economy-wide economic plans and production plans. A planned economy may use centralized, decentralized, participatory or Soviet-type forms of economic planning.

an economy in which building an investment, prices, and salary  are determined centrally by a rule.

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Explanation:

length of the cultivating season was not a problem of new england agriculture

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).