Q: Which gas do people exhale during each breath? Choices: - carbon monoxide - nitrogen - oxygen - carbon dioxide A:
carbon dioxide

Q: All living organisms are classified into one of six broad categories called what? Choices: - cities - tribes - nobles - kingdoms A:
kingdoms

Q: Q: Ionic bonds between two atoms require one metal and one what? Choices: - liquid - gas - metallic - nonmetal A:
A: nonmetal

Question: Q: When an atom gains or loses an electron it becames an? Choices: - electron - photon - neutron - ion A:
Answer: ion

*Question*
Q: Most of the energy used by living things comes either directly or indirectly from what? Choices: - plants - the moon - the soil - the sun A:
**Answer**
the sun

(Question)
Q: What type of cell layer do flatworms have? Choices: - epidermis - cuticle - endoderm - mesoderm A:
(Answer)
mesoderm