PLEASE HELP 1. Although organisms often share similar genes, they may have significant phenotypic differences. Which statement explains why this may occur?

Although DNA is always expressed, the gene products may not always be used by the organism.
Gene expression is controlled by regulatory genes, regulatory elements, and transcription factors.
Not all organisms have control mechanisms, so genes may sometimes be overexpressed or not expressed at all.
The types of nitrogenous bases differ between organisms, causing gene sequences to produce different proteins.