Animal Species Exhibit an Enormous Diversity of Genetic Information Contained

Animal species exhibit an enormous diversity of genetic information contained in nuclear DNA. This may be reflected in very different genome sizes. One might predict that animals with more complex structures might show greater numbers of different types of mRNAs during development. Scientists investigating this possibility were surprised to find that similar numbers of genes were transcribed at a particular time in development among species whose genomes differed greatly in size. How can this result be interpreted?

A) Some species retain large amounts of DNA that are never used.
B) The number of genes transcribed at any one time is tightly regulated and independent of genome size.
C) Nuclear DNA complexity is unrelated to the complexity of mRNAs transcribed during development.
D) Genome size has nothing to do with the physical complexity of the species.