a) Varieties of wheat which are the winter varieties would not normally flower in in a single flowering season available.

When they are planted in autumn, they take their time to germinate and over the winter period, seedlings are noticed which resumes its normal growth during the spring season so get harvested around the next midsummer.

b) Promotion of flowering under low temperature is called vernalization.

It is one of the important adaptations of plants growing at high altitudes to ensure that flowering occurs during the summer or warmer temperatures giving time for the development of seed in the plant.

c) The plant hormone that can replace the cold treatment is called gibberellin.

Plants that need cold treatment require photoperiodism to induce flowering in them. Without this treatment, vernalization has no effect. But it is observed that when these plants are treated with gibberellins (GA), they undergo flowering without subjecting the plants to cold environment and photoperiodism. Gibberellins are seen not only to substitute vernalization but also photoperiodism.

Vernalization- It is a process of cooling of seeds during its period of germination to induce faster flowering in them.

Photoperiodism: Physiological response of plants to day or night length or light exposure.