Step 1: Core idea of Democritus’ cosmology.
Democritus proposed an atomistic view of reality, according to which the cosmos is governed by necessity and order rather than chance or divine intervention.
Step 2: Nature of atoms.
Atoms are the fundamental constituents of reality. They are eternal, indivisible, indestructible, and possess extension and shape.
Step 3: Evaluation of options.
Option (A) is correct as Democritus believed in a rationally ordered cosmos.
Option (B) is correct because atoms are the basic units of reality.
Option (C) is correct since atoms are extended yet indivisible and indestructible.
Option (D) is incorrect because atoms are not shapeless or at rest; they are in constant motion.
Step 4: Conclusion.
Thus, options (A), (B), and (C) are correct.