*Question*
Q: Which type of substance is considered a proton donor in a reaction? Choices: - base - carbon - oxygen - acid A:
**Answer**
acid

*Question*
Q: What is the main greenhouse gas causing global warming? Choices: - nitrogen - sulfur - carbon monoxide - carbon dioxide A:
**Answer**
carbon dioxide

*Question*
Q: What branch of science is the study of matter and energy? Choices: - unnatural science - natural science - negative science - physical science A:
**Answer**
physical science

*Question*
Q: What type of behaviors do not have to be learned or practiced? Choices: - protective behaviors - acquired behaviors - diverse behaviors - innate behaviors A:
**Answer**
innate behaviors