*Question*
Q: Why are continents unable to be pushed down into the mantle by plate boundaries? Choices: - gravity - surface tension - density - buoyancy A:
**Answer**
buoyancy

*Question*
Q: What is the closed circulatory system of humans and other vertebrates called? Choices: - digestive system - reproductive system - respiratory system - cardiovascular system A:
**Answer**
cardiovascular system

*Question*
Q: What is the point on the ground that is located directly above where underground rocks fracture (or the "focus" point)? Choices: - danger zone - fault line - seismic point - epicenter A:
**Answer**
epicenter

*Question*
Q: On what part of bones would you expect to find cartilage? Choices: - interior - marrow - exterior - end A:
**Answer**
end