G2 of Interphase.
<P>
   A nuclear envelope bounds the nucleus.
<P>
   The  nucleus  contains  one  or  more  nucleoli,  where  ribosomes are
   synthesized.
<P>
   Chromosomes  have  been  duplicated, but are not yet visible under the
   light microscope.
<P>
   In animal cells, centrosomes are also replicated.