Each cell expresses, or turns on, only a fraction of its genes. the rest of the genes are repressed, or turned off. the process of turning genes on and off is known as gene regulation. gene regulation can occur at any point during gene expression, but most commonly occurs at the level of when the information in a gene's dna is transferred to mrna. a) post-translation b) replication c) transcription d) translation

The answer would be:

C. Transcription

Here's a little more about gene regulation:

Gene regulation as mentioned already, is the process of turning genes on and off. In multicellular organisms, the different cells have the same DNA in them but through gene regulation, different sets of genes are expressed. The genes that are expressed determine the function and appearance of the cell.

answer: a. a gene that causes a specific trait.