The two general types of vibrations produced by earthquakes are surface waves, which travel along the Earth's surface, and body waves, which travel through the Earth. ... The first indication of an earthquake is often a sharp thud, signaling the arrival of compressional waves.
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wouldn't that be the nervous system? or lymphatic system?
Explanation:The independent variable is the factor that you purposely change or control in order to see what effect it has. independent variable is defines as the variable that is changed or controlled in a scientific experiment. example: A scientist is testing the effect of light and dark on the behavior of moths by turning a light on and off. The independent variable is the amount of light and the moth's reaction is the dependent variable.