Final answer:
The exact number of spores a biological indicator should contain depends on the test's requirements and can vary. Biological indicators generally contain thousands to millions of spores. The age and environmental exposure history of spores impact their viability and growth in experimental settings.
Step-by-step explanation:
The question pertains to the recommended number of spores that should be present in a biological indicator. This specific information is not provided in the reference material, therefore I cannot give a definite answer to the intended choice between options A) 1 spore, B) 5 spores, C) 10 spores, D) 100 spores, or E) 1,000 spores. Generally, biological indicators are standardized to contain a specific number of spores, but this number can vary depending on the type of microorganism and the test's requirements. However, most commonly, a biological indicator contains thousands to millions of spores to ensure an adequate challenge to the sterilization process.
Biological indicators are used to verify the efficacy of sterilization processes. These indicators contain a known quantity of specific spores of a microorganism that is resistant to particular sterilization methods, such as autoclaving. To answer question 70, you could expect more growth in the flask containing endospores that are 20 years old compared to the ones that are 100 years old, assuming that the viability of spores decreases with time. However, if the 100-year-old spores were deposited before the contamination, as mentioned in the reference, they may exhibit more growth due to better resistance to the pollutant, which addresses option C.