What is signaled by nerve growth factor (NGF)?
a. That a target cell has accepted an axon
b. Which target cell a growing axon should connect with
c. That axons should elongate as the body grows bigger
d. The need for new neurons to form in brain areas that are lacking in neurons
Question 2
Leukocytes identify intruder cells by their ____
a. shape
b. chromosomal pattern
c. rate of cell division
d. surface proteins
