*Question*
Q: What kind of current flows in just one direction? Choices: - physical current - slow current - Alternating current - direct current A:
**Answer**
direct current

*Question*
Q: An increase in what, across the periodic table, explains why elements go from metals to metalloids and then to nonmetals? Choices: - neutrons - temperature - protons - electrons A:
**Answer**
electrons

*Question*
Q: Water, carbon dioxide, and what other element are important agents of chemical weathering? Choices: - helium - methane - sulfur - oxygen A:
**Answer**
oxygen

*Question*
Q: What would you need to see most cells? Choices: - ultraviolet - infrared - mirror - microscope A:
**Answer**
microscope