*Question*
Q: How is the radioactive decay measured? Choices: - carbon dating - quarter-life - alpha emission - half-life A:
**Answer**
half-life

*Question*
Q: Recrystallization is a process that can remove what, which result when compounds are synthesized? Choices: - chemicals - substances - minerals - contaminants A:
**Answer**
contaminants

*Question*
Q: The presence of what makes soil hold together more tightly and enables it to hold more water? Choices: - sand - salt - glass - clay A:
**Answer**
clay

*Question*
Q: Arguably the most important ingredient in saliva for digestion is a type of what, which initiates the breakdown of carbohydrates? Choices: - amino - genes - fatty - enzyme A:
**Answer**
enzyme