Which of the following is not produced in
fission reactions?

1. greenhouse gases
2. heat
3. isotopes
4.neutrons

1. greenhouse gases. these are not formed because nuclear fission involves the modification of atoms. It does not give rise to other molecules.

The one that is not produced in fission reactions is (1) Greenhouse gases

( Whisper)BTW i searched it up :)-

Remember that rust prevented by placing a sacrificial electrode in electrical contact with the iron. the sacrificial electrode must be composed of a metal that  oxidizes  more easily than iron (that is, it must be below iron in table 18.1).