Microstates have equal energy

[Danielle_Cho_3A]

Why do all of these 4 states have equal energy? In other words, what determines how much energy the system has?

[Chem_Mod]

You're asking two related but separate questions:

1) The microstates are said to have the same energy because they each represent a specific way a system orients itself to achieve a single macrostate. In other words, if many different microstates achieve the same macrostate (with a single set of measurable, macroscopic properties), the microstates are the same energy.

2) The internal energy describes a system's energy. It has two contributions: microscopic kinetic energy and microscopic potential energy.