AP BIOLOGY

Detailed explanation-1: -Photoperiodism is the regulation of physiology or development in response to day length. Photoperiodism allows some plant species to flower-switch to reproductive mode-only at certain times of the year.

Detailed explanation-2: -Photoperiodism is the response to changes in daylength that enables plants to adapt to seasonal changes in their environment. The best studied example of photoperiodism in plants is flowering, but other responses to daylength include bud dormancy and bulb or tuber initiation.

Detailed explanation-3: -Phototropism, or the differential cell elongation exhibited by a plant organ in response to directional blue light, provides the plant with a means to optimize photosynthetic light capture in the aerial portion and water and nutrient acquisition in the roots.

Detailed explanation-4: -Exposure to red light converts the chromoprotein to the functional, active form (Pfr), while darkness or exposure to far-red light converts the chromophore to the inactive form (Pr).