True or false: All cells in the system are identical to each other and work together?

The statement is false. In a given system, like the nervous system or circulatory system, there are various types of cells. Even though the entire system performs one function, the constituent cells may be contributing to different individual tasks that ultimately combine to carry out that function. 

In our body (or that of any complex organism), there are various levels of functionalities (or organization). At the most basic level is a cell. A number of cells that perform a given function constitute a tissue. A group of tissues working towards the same task form an organ. A number of organs that combine their functionalities to perform a common task constitute a system. Thus, the constituent cells need not be identical and do not perform the same task, yet collectively form a complex system that carries out a function.

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