The most common atom used in fission is uranium 232 uranium 235 uranium 238

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.

The answer is b im not sure 

Answerhave flowing water either episodically or during only a portion of the year;