66.The structure labeled A in the accompanying electron micrograph is
which of the following?
142 Anatomy, Histology, and Cell Biology
a. The site of translation of messenger RNA
b. Chromatin that is transcriptionally inactive during interphase
c. The site of ribosomal protein synthesis
d. A shield between the nucleus and cytoplasm in eukaryotic cells
e. The site of aqueous channels for the passage of molecules between the nucleo-
plasm and the cytoplasm
(Reproduced, with permission, from Fawcett DW: A Textbook of Histology, 11th ed.
Philadelphia:WB Saunders, 1986.)