Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Radioactivity is the release of particles and/or energy from the nucleus of an atom.
What is the release of particles and/or energy from the nucleus of an atom described as?

Most have cells that are not able to exchange gases with the outside environment do multicellular organisms need transport systems.
Why do multicellular organisms need transport systems?

Ac is better than dc for doing transporting electrcal energy.

Ac is better than dc for doing what?