Which one of the following statements is true for the phytochrome?

Which of the following is an example of a short-day plant?

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

Some plants require a period of light greater than a critical duration for flowering. Such plants are called $..............$.

Which proteinaceous pigment controls the light-dependent activities in plants?

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?