<prompt> Memory cells dont undergo apoptosis due to the presence of which growth factor?Platelet derived growth factorNerve growth factorInsulin like growth factorFibroblast growth factor  <response>: Nerve growth factor was the first identified protein with anti-apoptotic activity on neurons. This prototypic neurotrophic factor, together with the three structurally and functionally related growth factor. Hence nerve cells don;t undergo apoptosis. 