Choose the correct answer:
1. Joining of lighter nuclei to make a heavier nucleus, most commonly hydrogen isotopes to helium such as
\(2H\) \(+\) \(2H\) \(\rightarrow\) \(3He\) \(+\) \(n\)
with release of large amount of energy is __________.
\(2H\) \(+\) \(2H\) \(\rightarrow\) \(3He\) \(+\) \(n\)
with release of large amount of energy is __________.
2. Nuclear reactions occurs at __________.