1. The problem asks whether Cavalieri's principle states that two solids with equal heights and cross-sectional areas at every level have equal volumes. 2. Cavalieri's principle is a geometric theorem used to compare volumes of solids. 3. The principle states: If two solids have the same height and the areas of their cross-sections at every corresponding level are equal, then the volumes of the two solids are equal. 4. This means that the volume depends on the height and the cross-sectional area at each level. 5. Therefore, the statement given is true. **Final answer:** A. True