*Question*
You are presented with the question "The emission of what causes acid rain?" and the following answer choices: - H2O - smoke from food - Hydrogen - coal - SO2 - oil - CFCs - Cars Now knowing that the emission of sulfur dioxide causes acid rain and it's sulfur dioxide (SO2), choose the best answer.
**Answer**
SO2

*Question*
You are presented with the question "What do guitar strings do?" and the following answer choices: - Charge the guitar - Relieve pain - Vibrates - reproduce - squeeze - Bend - Create silence - Mute the guitar Now knowing that matter vibrating can cause sound and all guitars produce sound through the mechanical vibration of strings, choose the best answer.
**Answer**
Vibrates

*Question*
You are presented with the question "What is in fruit? " and the following answer choices: - trees - flowers - seeds - food - sugar - blood - kidneys - sulfur Now knowing that sugar causes food to taste sweet and fruit is delicious and very sweet, choose the best answer.
**Answer**
sugar

*Question*
You are presented with the question "What has led to the increase in global warming?" and the following 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 Now knowing that carbon dioxide concentrations in the air have increased over the last decade dramatically and carbon dioxide is the chief culprit in the increased threat of global warming in recent decades, choose the best answer.
**Answer**
Increase in carbon dioxide