*Question*
Q: The conducting zone of the respiratory system includes the organs and structures not directly involved in what?    Choices:  - copper exchange  - helium exchange  - gold exchange  - gas exchange  A:
**Answer**
gas exchange

*Question*
Q: As lava cools, tiny iron-rich crystals line up with earth’s what?    Choices:  - gravitational field  - oceans  - molecular field  - magnetic field  A:
**Answer**
magnetic field

*Question*
Q: How many chambers are in a reptiles heart?    Choices:  - ten  - two  - five  - three  A:
**Answer**
three

*Question*
Q: What is the smallest aromatic hydrocarbon?    Choices:  - furan  - sulfide  - phosphate  - benzene  A:
**Answer**

benzene