In the related links below, I posted the information.
vikkali
Nuclear fussion
Fussion
Both release excess nuclear binding energy.
The cores of stars and hydrogen bombs.
no, but the products of fission are radioactive
There is a lower risk of runaway chain reactions.
Nuclear fussion of Hydrogen to give helium, positron and energy
Very carefully
Light elements combined to form the heavier elements.
Only at the core where the temperature and pressure is high enough.
If you're referring to nuclear energy in power generating plants, it is nuclear fission. If you're referring to the nuclear energy in our Sun, it is nuclear fusion.