During glacial periods in the early evolution of land plants, which of the following would have been a beneficial adaptation regarding the number of stomata per unit surface area, and what accounts for it?
A) increased numbers of stomata, to maximize absorption of increasing levels of atmospheric CO2
B) increased numbers of stomata, to maximize ability to absorb low levels of atmospheric CO2
C) decreased numbers of stomata, to retain CO2 produced by the chloroplasts
D) decreased numbers of stomata, to maximize absorption of low levels of atmospheric CO2
