Describe each type of economic system

Command economic system is the next step up from a traditional economy. This by no means indicates that it is fairer or an exact improvement; there are many things fundamentally wrong with a command economy.

A market economy is very similar to a free market. The government does not control vital resources, valuable goods or any other major segment of the economy. 

A mixed economic system (also known as a Dual Economy) is just like it sounds (a combination of economic systems), but it primarily refers to a mixture of a market and command economy (for obvious reasons, a traditional economy does not typically mix well).

the  seven  days  battles  were  a series of seven battles over seven  days from june 25 to july 1, 1862, near richmond, virginia,  during  the american civil war. the  seven  days ended with mcclellan's army in relative safety next to the james river, having suffered almost 16,000 casualtiesduring  the retreat.

the correct answer is b.