Answer: MEDIUM
A sterile substance that allows for microorganism multiplication is known as a medium.
Explanation: A medium is a microbiological substance either solid or liquid that is used to grow bacteria.
A medium contains everything a bacteria needs to grow outside the body and under laboratory conditions. It is made free of all forms of viable microbes(sterile) and enriched with special growth factors that aid in the growth of organisms that have complex or distinct nutritional requirements.
These nutrients may be organic substances such as blood, serum extracts of animals,plants or yeast, meat extracts(cell secretions), or haemoglobin.