Microbiology Which of the following events occur first in the differentiation sequence of human B cells in the bone marrow? A Cytoplasmic mu chains present in the B cell B Immunoglobulin heavy chain rearrangement C Immunoglobulin light chain rearrangement D Surface IgD and IgM present on the B cell 💡 Explanation Which of the following events occur first in the differentiation sequence of human B cells in the bone marrow? ✓ Correct Answer: B. Immunoglobulin heavy chain rearrangement