Final answer:
The enzymes/proteins utilized for the development of B cells and T cells and the establishment of junctional diversity are RAG-1 & RAG-2 and TdT (Terminal deoxynucleotidyl transferase).
Step-by-step explanation:
The correct answer is A & C. For the development of B cells and T cells and the establishment of junctional diversity, two enzymes/proteins are utilized: RAG-1 & RAG-2 and TdT (Terminal deoxynucleotidyl transferase). RAG-1 & RAG-2 are responsible for the rearrangement of gene segments (V, D, and J) that encode for BCRs and TCRs, leading to the assembly of diverse receptors. TdT, on the other hand, introduces random nucleotide additions during the rearrangement process, further contributing to the diversity of BCR and TCR sequences