Biennials and perennial plants are stimulated to produce flowers by exposing them to low temperature. In these plants, the low temperature stimulus is received by the I. Shoot apex of a mature stem II. Embryo of the seed III. Leaves

Explanation

Only option I and II are correct as In many biennials (e.g., carrot, beet) and some perennials, the shoot apical meristem is the site where vernalization occurs.The shoot apex contains meristematic tissue, which can respond to cold and later initiate flowering when conditions become favorableIn some plants, especially winter annuals and cereals like wheat, barley, and rye, the embryo inside the seed perceives the cold treatment.(option I)Seeds are exposed to low temperatures (called stratification) to break dormancy and promote flowering after germinationLeaves are not the primary site for vernalization.(option II)Although leaves can sense photoperiod (day length) through phytochrome, they cannot perceive cold stimulus for vernalization.The cold must act on meristematic tissues, not on mature leaf cells, which lack the ability to initiate flowering signals in response to cold.(option III)