Final answer:
Bt is biodegradable and known to have a short persistence time. It is a naturally occurring bacterium used as a biological pesticide in organic farming.
Step-by-step explanation:
The substance that is biodegradable and known to have a short persistence time is E) Bt. Bt, or Bacillus thuringiensis, is a naturally occurring bacterium that produces toxins that are harmful to certain insects but have minimal impact on other organisms and the environment. It is commonly used as a biological pesticide in organic farming. Bt breaks down relatively quickly in the environment, making it a good alternative to chemical pesticides that persist for longer periods.