select all of the following that are true about growth factors triggering cell division.
A. growth factors bind receptors on the cell membrane.
B. growth factors are only found in animal cells.
C. in response to a signal, a cascade of chemical reactions inside the cell initiates cell division.
D. growth factors "Wal" along microtubules to receptors on the nuclear membrane.
E. a growth factor stimulates the production of new skin cells at a wound site.
F. growth factors normally act to block exit of the cell from the G1 phase of the cell cycle, thereby suppressing cell division.
