*Question*
If the emission of SO2 causes acid rain, then the emission of what causes acid rain? Answer choices: - H2O - smoke from food - Hydrogen - coal - SO2 - oil - CFCs - Cars
**Answer**
SO2

*Question*
If guitar strings vibrate, then what do guitar strings do? Answer choices: - Charge the guitar - Relieve pain - Vibrates - reproduce - squeeze - Bend - Create silence - Mute the guitar
**Answer**
Vibrates

*Question*
If sugar is in fruit, then what is in fruit? Answer choices: - trees - flowers - seeds - food - sugar - blood - kidneys - sulfur
**Answer**
sugar

*Question*
If the rise in carbon dioxide concentrations contributes to the increase in global warming threats, then what has led to the increase in global warming? Answer choices: - Greenhouse gases - movements in the earth's crust - Increase in carbon dioxide - Greenhouse gasses - forest is destroyed - Burning fuel and air - movement of tectonic plates - tectonic plates being pushed together
**Answer**
Increase in carbon dioxide