Question Detail
Question
Why might an undefined medium be chosen over a defined medium?
Correct Answer
Option D is the correct answer.
Detailed Explanation
Undefined media (also known as complex media) contain ingredients like yeast extract or peptone, which have unknown exact chemical compositions. This makes them rich in various nutrients and growth factors, allowing them to support the growth of a wider range of microorganisms, especially fastidious ones, that might not grow on a chemically defined medium. While often less expensive (option C), the primary reason for selection is usually its broad growth support.
Hint
Consider the nature of an undefined medium – what does 'undefined' imply about its ingredients and its effect on microbial growth?