Phytochrome is associated with which of the following processes?

Which light is most effective in inducing seed germination?

Photoperiod is an important factor which affects

When all parts except the leaves of a short-day plant are covered with a light-proof cover and then subjected to short-day light/dark treatment,it will produce flower buds. When a portion of this plant is grafted onto another plant of the same species which has been prevented from flowering by excessive exposure to light,this latter plant will also produce flower buds. Which is the best inference from this result?

$A$ plant which needs not less than $10$ hours of light to flower is:

Which of the following pigments absorbs red and far-red light?