Production of a human protein in bacteria by genetic engineering is possible because:

The production of a human protein in bacteria by genetic engineering is possible because the genetic code is universal. The genetic code is the set of rules that determines how the sequence of nucleotides in DNA is translated into the sequence of amino acids in a protein. Since the genetic code is the same in all living organisms, it is possible to express a human gene in a bacterial cell and produce a human protein. So, the correct answer is option D. Notice that the other options are not correct. Bacterial cells are not capable of carrying out RNA splicing reactions, human chromosomes cannot replicate in bacterial cells, and the mechanism of gene regulation is not identical in humans and bacteria.