Which is NOT involved at the beginning of a nerve impulse?
A. reaching the threshold
B. strong stimulus
C. sodium leaving the cells
D. negative charge inside the cell

Which of the following is most important in making the typical seed more resistant to adverse conditions than the typical spore? a) a different type of sporopollenin b) an internal reservoir of liquid water c) integument(s) d) ability to be dispersed e) waxy cuticle