Q1. In examining a picture of the cell taken with an electron microscope, a student observes that the cell has a nucleus and a cell membrane but not a cell wall. The student can accurately conclude that the cell is a what?

Q2. According to clonal selection theory, all the immunoglobulin molecules on a single B cell have the same antigenic specificity. Describe why the presence of both IgM and IgD on the same B cell does not violate single specificity implied by clonal selection.