An aliquot is:

• A. A portion of a well-mixed sample removed for testing
• B. The entire sample
• C. A measurement of pH
• D. A type of bacteria

Answer: (A)

An aliquot is a portion of a well-mixed sample removed for testing. This lets you analyze a representative subset without handling the entire sample, which helps ensure the test results reflect the whole sample and makes it practical to run multiple analyses. The entire sample isn’t an aliquot because it’s the whole amount, not a subset. A measurement of pH is something you obtain from testing, not the portion itself. A type of bacteria is unrelated to the idea of a sample portion.