Answer:
mechanical waves
Explanation:
They require a medium to travel through.
Sound and water waves are mechanical waves; meaning, they require a medium to travel through. The medium may be a solid, a liquid, or a gas, and the speed of the wave depends on the material properties of the medium through which it is traveling.
radioactive dating of each layer would be the right one
b. they are both asymmetrical. Placozoans have endoderm and ectoderm while sponges have no tissue.
