Why are seismic waves considered mechanical waves?
A. They must travel through a medium, such as
the bedrock of the Earth.
B. They will only travel through empty space.
C. They travel in circles.
D. They do not require a medium.

The correct answer is - option A.

Explanation:

The seismic waves are the waves that are the result of an explosion or the breaking of the rock within the earth. In other words, when these explosions or breaking cause an energy transfer within the earth are seismic waves. Seismic waves require a medium to travel and normally it is the earth.

The bedrock of earth is a great example of a medium for traveling these waves that make it a mechanical wave. Earthquake is the result of such waves.

answer: - b cells

explanation: -

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.