Respuesta :
its 235 it makes up about .6 to.7 of natural uranium but it the only isotope that supports chain reaction fission.
Answer:
uranium 235
Explanation:
- For a fusion reaction to take place the dominant radioactive substance is the U-235 that has isotopes of the iodine, the cesium, the strontium, the xenon, and the barium also. And is done by splitting the smaller nuclei of the neurons and the release of the heat. And the fusion gives about 90% of the helium.