The correct options are:
A. They travel at varying speeds, depending on the composition of layer.
B. They are deflected while passing through layers of different compositions.
D. S-waves cannot pass through a layer of liquid composition.
P-waves (primary waves) and S-waves (secondary waves) are two types of seismic waves generated by earthquakes and other sources of seismic activity. These waves travel through the Earth's interior and are affected by the physical properties of the different layers they pass through.
P-waves are compressional waves that travel through solid and liquid materials, and they move faster than S-waves. They can travel through the Earth's core and are refracted and reflected as they pass through layers of different densities, allowing scientists to study the interior of the Earth.
S-waves are transverse waves that can only travel through solid materials, and they move slower than P-waves. When they encounter a layer of liquid material, they are unable to pass through it and are reflected back to the surface, creating a shadow zone on the opposite side of the Earth from the earthquake. This allows scientists to determine the size and shape of the Earth's liquid outer core.
Thus, options A, B, and D are correct, and option C is incorrect because both P-waves and S-waves are produced during earthquakes and volcanic eruptions.