  In this paper, we study the fine Selmer groups attached to a Galois module
defined over a commutative complete Noetherian ring with finite residue field
of characteristic p. Namely, we are interested in its properties upon taking
residual representation and within field extensions. In particular, we will
show that the variation of the fine Selmer group in a cyclotomic
$\Zp$-extension is intimately related to the variation of the class groups in
the cyclotomic tower. We also discuss some examples of pseudo-nullity of fine
Selmer groups.
