Keara’s class is modeling lava flow from volcanoes. Each of the three common types of lava has a different thickness. Keara and her classmates want to know if the type of lava affects how fast it flows from a volcano. Which variable should they test?

To find out whether lava type affects flow speed, the class should test a feature that differs among the lava types. The question says the three types have different thicknesses, so they should test the thickness of the lava. The volcano’s size, lava temperature, and volcano location are not identified as differences among the lava types.

AI-written and checked against the verified answer.