1. in any nuclear reaction, nuclei are transformed in some way.

true
false
2. two fissionable substances commonly used in nuclear reactors and nuclear weapons include uranium-235 and plutonium-239.

true
false
3. fission reactions can be controlled; thus, they are used to create energy and electricity. but fusion reactions are uncontrollable and require too much energy for economical use.

true
false
4. fission reactions occur at such high temperatures in the sun that the sun appears to glow.

true
false

1. In any nuclear reaction, nuclei are transformed in some way.

True

2. Two fissionable substances commonly used in nuclear reactors and nuclear weapons include uranium-235 and plutonium-239.

True

3. Fission reactions can be controlled; thus, they are used to create energy and electricity. But fusion reactions are uncontrollable and require too much energy for economical use.

True

4. Fission reactions occur at such high temperatures in the Sun that the Sun appears to glow.

False

Hope this answers the question. Have a nice day.

Answer) by studying proton collisions hope this : )