*Question*
Answer the following question given this paragraph: Unlike oxygen, carbon dioxide is more concentrated in the blood in the capillaries surrounding the alveoli than it is in the air inside the alveoli. Therefore, carbon dioxide diffuses in the opposite direction. It moves out of the blood and into the air. Q: Which gas moves from the blood in the capillaries into the air? Choices: - nitrogen - carbon monoxide - oxygen - carbon dioxide A:
**Answer**
carbon dioxide

*Question*
Answer the following question given this paragraph: Craters and rifts become lakes when they fill with water. Where does the water come from?. Q: What do craters and rifts become when the fill with water? Choices: - rivers - creeks - grasses - lakes A:
**Answer**
lakes

*Question*
Answer the following question given this paragraph: When matter reacts, there can be mass that comes from nowhere and is unaccounted for. Q: When matter reacts, there can be what that comes from nowhere and is unaccounted for? Choices: - concentrations - combustions - bonds - mass A:
**Answer**
mass

*Question*
Answer the following question given this paragraph: An aquifer is a layer of saturated porous rock. It lies below the water table. An impermeable layer, such as clay, is below the aquifer. Q: What is a layer of saturated porous rock? Choices: - a shear - an overhang - a quarry - an aquifer A:
**Answer**
an aquifer