I want to know the answer to the following question:
What was only incorporated into Layer III and not Layers I or II?
All the background I'm provided with is that "Much of its technology and ideas were incorporated into the definition of ISO MPEG Audio Layer I and Layer II and the filter bank alone into Layer III (MP3) format as part of the computationally inefficient hybrid filter bank.". Is that enough to answer the question?
Answer: yes