Importance of day length in flowering of plants was first shown in

Nicotiana tabacum,a short-day plant,when exposed to more than the critical period of light,fails to flower. Explain.

One set of a plant was grown at $12$ hours day and $12$ hours night period cycles and it flowered,while in the other set,the night phase was interrupted by a flash of light and it did not produce flowers. Under which one of the following categories will you place this plant?

An example of a short-day plant is:

If the dark period is interrupted by red light in $SDP$,the plant will show:

Analogy type questions:
$(1)$ Coconut milk : Zeatin : : $ABA$ : ...............
$(2)$ Phenolic acid : Seed dormancy : : Cold treatment : ...............