Final answer:
Growth factors are a class of extracellular cues that are important for flipping the switch for signaling pathways. They bind to cell-surface receptors and stimulate cell growth and division.
Step-by-step explanation:
The class of extracellular cues that is important for flipping the switch for signaling pathways is growth factors. Growth factors are ligands that bind to cell-surface receptors and stimulate cell growth and division. They activate a signaling pathway that includes protein kinases, such as receptor tyrosine kinases (RTKs), which then trigger the activation of downstream signaling molecules, ultimately leading to cell division.