<prompt> Which of the following growth factor maintain the neurons by reducing apoptosis therefore the memory cells does not undergo apoptosis?Platelet derived growth factorNerve growth factorInsulin like growth factorFibroblast growth factor  <response>: The first neurotrophin to be characterized was nerve growth factor NGF, a protein growth factor that is necessary for the growth and maintenance of sympathetic neurons and some sensory neurons. NGF is picked up by neurons and is transpoed in retrograde fashion from the endings of the neurons to their cell bodies. It is also present in the brain and appears to be responsible for the growth and maintenance of cholinergic neurons in the basal forebrain and the striatum. There is evidence that the maintenance of neurons by NGF is due to a reduction in apoptosis. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. 2012. Chapter 4. Excitable Tissue: Nerve. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks Eds, Ganongs Review of Medical Physiology, 24e. 