I & II Both seismic waves (that cause earthquakes) and sound waves (which sonar uses) can be compressed because they are longitudinal. All other wave types are electromagnetic waves and cannot be compressed.
Always wear goggles! This is to prevent chemicals or any other substance to get into your eyes. If this wasn't followed, more people could get hurt.
Clean up afterwards! Its always better to clean up so someone else couldn't get hurt! If people don't follow this, it could be a mess and someone could get seriously injured.
When smelling something, waft it to your face, and not get real close. This is to prevent getting chemicals into your body that could be poisonous. If people didn't folloe this, someone could be seriously sick.
