Final answer:
The pH scale is a range of values from 0 to 14 that describes the acidity or basicity of a solution. Bacteria can be affected by acidity because extreme pH levels can disrupt the structure and function of macromolecules, such as DNA and proteins.
Step-by-step explanation:
The pH scale is a range of values from 0 to 14 that describes the acidity or basicity of a solution. Solutions with pH less than 7 are acidic, pH 7 is neutral, and pH greater than 7 is basic. Bacteria can be affected by acidity because extreme pH levels can disrupt the structure and function of macromolecules, such as DNA and proteins, which are essential for bacterial survival and activity.