Why do science textbooks tend to focus on three states of matter rather than four?

Match the following items. match the items in the left column to the items in the right column. 1. general or nonspecific observation best fit curve 2. educated guess quantitative 3. when two variables change in the same direction, one remaining larger than the other by the same factor theory 4. "measured" observation control 5. standard, reference data, or experiment qualitative 6. a presently accepted explanation of how something happens law 7. a statement that explains what something does under the same conditions hypothesis 8. a curve drawn to average the data's deviations direct relationship