Biology 1st Edition by Jerome Krueger, Kendra Hill, Robert Noyd

تمرين 11

Pine trees are wind-pollinated plants. The distance that a pollen grain travels is determined by three factors that are observed in nature: (1) the height at which it is released, (2) the air flow or wind currents that it catches, and (3) how long the pollen grain can stay aloft. A pine pollen grain has two winglike projections that contain gas ( Fig. ). Which of the three factors is maximized by this structure?
Figure Pine pollen grain.