Problem: David was studying for his chemistry exam. To understand the elements of the periodic table better he categorized them into three groups, cat A, cat B, and cat C. In cat A he placed all the elements with atomic numbers lower than 83. In cat B he put the elements with atomic numbers from 83 to 94. Finally, in cat C he placed the elements with atomic numbers over 94. He found it easier to see their differences after he categorized them. Would cat A more likely or less likely show radioactive decay than cat B?

A: less likely

Problem: Jordan and Elizabeth are performing a chemistry experiment for the science fair. Jordan uses a high concentration of the reactants when starting his reactions. Elizabeth uses a low concentration of the reactants when she starts her reactions. Who will have reactions with more frequent collisions between the reactant molecules?

A: Jordan

Problem: Greg and Paul were two neighbors. They were both into mycology. Greg researched AM fungi, while Paul studied other types of mycorrhizal fungi. Which researcher learned more about plants allocating less carbon to AM fungi?

A: Greg

Problem: Tom and John are both pool owners. Tom prefers to use sodium bisulfate in his pool because he enjoys the smell. John, however, prefers using sodium carbonate in his pool because he believes it helps keep pests away. Whose pool will have lower levels of carbon dioxide?

A:
Tom