Questions: What are the two primary types of waves generated by earthquakes?

The answer is the fourth one: surface waves and body waves.

Explanation for each option:

1. S waves and body waves: This option is incorrect because S waves are a type of body wave. Body waves include both P waves and S waves.

2. P waves and S waves: This option is partially correct but not complete. P waves and S waves are indeed the two types of body waves, but the question asks for the primary types of waves generated by earthquakes, which include both body waves and surface waves.

3. horizontal surface waves and surface waves: This option is incorrect because it redundantly mentions surface waves twice and does not cover body waves.

4. surface waves and body waves: This is the correct answer. Earthquakes generate two primary types of waves: body waves (which include P waves and S waves) and surface waves (which include Love waves and Rayleigh waves).

5. horizontal surface waves and vertical: This option is incorrect because it does not accurately describe the primary types of waves generated by earthquakes. It incorrectly categorizes surface waves without mentioning body waves.

Summary: The two primary types of waves generated by earthquakes are surface waves and body waves.