The leaves at the top of a tree’s canopy are exposed to direct sunlight during the day, and their phytochromes will occur in a high ratio. Meanwhile, the leaves of the same tree at the bottom of the canopy are highly shaded during the day and will likely have a higher proportion of the form of phytochrome present due to exposure to a higher proportion of light.

Explanation:

1)Pfr/Pr

2) Pr

3)far-red

Explanation:

The leaves at the top of a tree’s canopy are exposed to direct sunlight during the day, and their phytochromes will occur in a high *Pfr/Pr* ratio. Meanwhile, the leaves of the same tree at the bottom of the canopy are highly shaded during the day and will likely have a higher proportion of the * ( PHYTOCHROME )Pr *;form of phytochrome present due to exposure to a higher proportion of *FAR RED * light.

Plants make use of the phytochrome system to it's adjust growth based on the seasons. Through phytochrome plants is able to respond to the timing and duration of dark and light periods. At dawn, all the phytochrome molecules present in the leaved are converted to the active Pfr form until sunset this is because the sun is unfiltered, and unfiltered sunlight has high percentage of red light, but lower far-red light, with the help of phytochrome system , the plants is able to compare the length of dark periods over several days.