Answer: the relative differences in arrival times of the S and P seismic waves at several recording stations tell scientists about the different speeds those waves were traveling at, which in turn gives information about the density of the material the layer is made of, and how thick the layer is in several directions.
Explanation:Earth's layers
B because a new species adds more diversity to your ecosystem
Answer: B - A battery with wires
Explanation: The mitochondria is the cells source of energy
