*Question*
Answer the following question given this paragraph: When current flows in just one direction, it is called direct current (DC) . The diagram below shows how direct current flows through a simple circuit. An example of direct current is the current that flows through a battery-powered flashlight. In addition to batteries, solar cells and fuel cells can also provide direct current. Q: What kind of current flows in just one direction? Choices: - physical current - slow current - Alternating current - direct current A:
**Answer**
direct current

*Question*
Answer the following question given this paragraph: The increase in electrons across the periodic table explains why elements go from metals to metalloids and then to nonmetals from left to right across the table. Look at period 2 in Figure below as an example. Lithium (Li) is a metal, boron (B) a metalloid, and fluorine (F) and neon (Ne) are nonmetals. The inner energy level is full for all four elements. This level has just one orbital and can hold a maximum of two electrons. The outer energy level is a different story. This level has four orbitals and can hold a maximum of eight electrons. Lithium has just one electron in this level, boron has three, fluorine has seven, and neon has eight. 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*
Answer the following question given this paragraph: Water, carbon dioxide, and oxygen are important agents of chemical weathering. Q: Water, carbon dioxide, and what other element are important agents of chemical weathering? Choices: - helium - methane - sulfur - oxygen A:
**Answer**
oxygen

*Question*
Answer the following question given this paragraph: Most cells are so small that you cannot see them without the help of a microscope . It was not until 1665 that English scientist Robert Hooke invented a basic light microscope and observed cells for the first time, by looking at a piece of cork. You may use light microscopes in the classroom. You can use a light microscope to see cells ( Figure below ). But many structures in the cell are too small to see with a light microscope. So, what do you do if you want to see the tiny structures inside of cells?. Q: What would you need to see most cells? Choices: - ultraviolet - infrared - mirror - microscope A:
**Answer**
microscope