Sentences of a paragraph are given below. While the first and the last sentences are in the correct order, the sentences in between are jumbled up. Arrange the sentences A, B, C and D in the correct order to form a meaningful and coherent paragraph.

S1: Radiation is often categorized as either ionizing or non-ionizing depending on the energy of the radiated particles.
S2: __________
S3: __________
S4: __________
S5: __________
S6: These particles constitute the secondary cosmic rays that are produced after primary cosmic rays interact with Earth's atmosphere.
Options:
A: Ionizing radiation carries more than 10 eV, which is enough to ionize atoms and molecules and break chemical bonds.
B: This is an important distinction due to the large difference in harmfulness to living organisms.
C: Other sources include X-rays from medical radiography examinations and muons, mesons, positrons, neutrons and other particles.
D: A common source of ionizing radiation is radioactive materials that emit α, β, or γ radiation, consisting of helium nuclei, electrons or positrons, and photons, respectively.