Which process contributes to the formation of layers in protoplanets when unstable elements release particles and energy?

compaction

O evaporation

O radioactive decay

O collision of space materials

Radioactivity occur when an unstable nucleus changes to a stable configuration this is done by releasing some particles.

The Emission of energy in form of Ionizing radiation is Radioactive decay.

The time taking for a radioactive decay to occur is half life.

The emission of this material are usually in form of alpha particle, beta particle and gamma rays.

Radioactive material are said to be life threatening because of it adverse effect on humans. It could lead to mutation when exposed to excessively, abortion of foetus, cancerous cells growth.