Differences expensive cheap physical models please help me I will give 30points

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

Under normal conditions, describe how increasing the temperatures effects the solubility of a typical salt

Coal contains energy. a. light b. kinetic c. chemical d. mechanical