Think of an experiment to prove that mushrooms need oxygen.

Mushrooms are living things and, like all living things, they need oxygen to breathe and oxidize carbohydrates.
This can be proven through experience: take a jar, put mushrooms there and close the jar with a lid. There is some oxygen in the jar. After 2 days, open the lid and put a lighted match or candle in the jar – it will go out, because there is no oxygen in the jar to support combustion. The mushrooms have used it up.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.