Answer:
c. regulating gene expression
Explanation:
During development, early embryo cells release different ligand molecules that bind to specific receptors on the surface of nearby cells, thereby triggering signaling pathways involved in cell differentiation and development. These signaling events have been associated with the activation of transcription factors located in the cytoplasm which are then translocated into the nucleus where they activate the transcription of target genes. For example, sonic hedgehog (SHH) is a peptide hormone that plays roles during animal development. SHH is secreted by epithelial cells to activate transcription factors in nearby cells involved in several developmental processes.
