What do the key results indicate?

Idon’t quite understand this problem

Juan created a chart to him study for a test. which headings best complete the chart? x: transparent objects y: opaque objects x: opaque objects y: transparent objects x: high frequency waves y: low frequency waves x: low frequency waves y: high frequency waves

In which type of system is power held solely by the central government and not shared with regional governments? group of answer choices federal unitary confederate oligarchic