Answer:
(C) receptor-ligand binding, signal transduction, cellular response, change in gene expression
Explanation:
During cell signaling, the signaling cells release specific signaling molecules, called ligands that bind to the specific receptors present on the target cells or the responding cells. Here, the signaling molecule can be neurotransmitters, hormones, and other regulatory molecules. As a ligand binds to its receptors present on the target cell, the reception of the signal by the target cell occurs.
The binding of the ligand to the receptor activates the later which in turn converts the extracellular signal into the intracellular signal. The process is called signal transduction. During signal transduction, some changes in the target cell occur followed by the generation of specific responses by the cell. The cellular response may involve an altered pattern of gene expression.
