Final answer:
The average number of neutrons released per 235U fission is 2-3.
Step-by-step explanation:
The average number of neutrons released per 235U fission is 2-3. During the fission process, a large nucleus like 235U undergoes a chain reaction, producing two to three neutrons as a result. These released neutrons have the potential to cause the fission of other nuclei, continuing the chain reaction.