Radiation is energy that originates from a source and flows through space at the speed of light.
Ionizing radiation changes DNA and causes mutation.
It can directly create a break in the double-stranded DNA or it can encourage the creation of reactive oxygen species, which can induce a single-strand break in the DNA and cause further DNA damage.
Radiation can change any cell's DNA.
Somatic or non-heritable effects are those that are caused by mutations in somatic cells and solely affect the organism in which the mutation occurred.
They include cell damage and death.
Even though the synthetic bonds that hold DNA strands together are strong enough, they cannot tolerate exposure to radiation indefinitely, repeatedly, or for extended periods.
Ionizing radiation can act like an axe on a piece of wood as soon as it contacts them, breaking important connections and damaging or erasing these important DNA components.
It can also have a dispersive effect, in which the effects are not noticed immediately, but tend to pile up and become apparent over time.