Define/Explain: Photoperiodism.

Which of the following is a short-day plant?

For the germination of seed,which light is necessary?

Assertion $(A)$: Vernalization is the acceleration of subsequent flowering by low-temperature treatment.
Reason $(R)$: The site of vernalization is the apical meristem.

Given below are two statements.
Statement $I$: If the long dark period is interrupted by a brief flash of light,short day plants will not flower.
Statement $II$: When the long dark period is interrupted by a brief flash of light,long day plants can flower.
In the light of above statements,choose the most appropriate answer from the options given below:

The site of perception of light in plants for flowering is