Plants typical of the tundra are very short in stature or height. what is advantageous about this so called 'cushion plant form found in the tundra, relative to a tall plant?
a. wind speeds are lower closer to the ground, reducing convective heat loss from plants
b. daytime air temperatures are usually higher closer to the ground, leading to higher convective heat gain by leaves
c. daytime conductive heat gain from adjacent ground surface would be greater
d. all the above
e. b and c