No any of the organelle which is bounded by membranes.
I believe that the most common antibody switch is from IgM to IgG.
Class switching occurs by a mechanism called the class switch recombination binding. It is a biological mechanism that allows the class of antibody produced by an activated B cell to change during a process known as isotype or class switching. The mechanism changes a B cell's production of antibodies from one form to another, such as from the isotype IgM to the isotype IgG.
Replication is the process by which a cell duplicates the DNA.
Vestigial structures<span> are often homologous to </span>structures<span> that are functioning normally in other species</span>
