Out of nearly 5000 protein-coding gene families, there is a set of nearly 300 conserved gene families that are found in species from all domains of life. When one looks at the general functions assigned to these gene families, it is found that …

A) the majority of them function in cell-to-cell signaling.
B) the majority of them are poorly characterized.
C) more than one-third of them are involved in translation or amino acid transport and metabolism.
D) more than one-half of the shared families are involved in DNA replication and transcription.
E) Nearly all of them are involved in energy production and carbohydrate metabolism.