Question

multiple choice question
the medium whose recipe appears below is a chemically complex medium because ______.
27.5 grams\tbrain, heart extract, peptone extract
2 grams\tglucose
5 grams\tsodium chloride
2.5 grams\tdisodium hydrogen phosphate

options:

• it contains four different ingredients
• there are different quantities of each ingredient
• ingredients like brain or heart extract may vary from batch to batch
• the medium must be buffered to ph of 7.0 before use
• it contains a number of chemical elements, like sodium, chloride, hydrogen, and phosphate

rate your confidence to submit your answer.

Explanation:

A chemically complex medium has components (like brain/heart extract) with undefined, variable compositions between batches. Other options: ingredient count/quantities don't define complexity; buffering or chemical elements (from defined compounds) don't make it complex. So the correct reason is about variable extracts.

Answer:

C. ingredients like brain or heart extract may vary from batch to batch (assuming the option with this text is labeled C; adjust label as per original question's numbering)