Zygote Dormancy in Fertilised Ovules — NEET Biology

Correct answer: A — I → II → V → III → VI → IV

Let's arrange the events in chronological order: 1. **I. Division of generative cell to form two male gametes**: In many angiosperms (3-celled condition), the generative cell divides to form two male gametes before pollen shedding. In others (2-celled condition), this division occurs during pollen tube growth in the stigma or style. 2. **II. Entry of pollen tube into the synergid**: After landing on the stigma and germinating, the pollen tube grows through the style and enters the ovule, typically through the micropyle, and then enters one of the synergids. 3. **V. Formation of diploid zygote**: One of the male gametes released into the synergid fuses with the egg cell (syngamy) to form a diploid zygote. 4. **III. Formation of triploid primary endosperm nucleus**: The other male gamete fuses with the two polar nuclei (triple fusion) to form the triploid primary endosperm nucleus (PEN). Syngamy and triple fusion occur almost simultaneously. 5. **VI. Formation of globular embryo**: The zygote then undergoes development, passing through stages like proembryo, globular, heart-shaped, and eventually mature embryo. The globular embryo is an early developmental stage. 6. **IV. Development of ovule into seed**: After fertilisation, the ovule matures and transforms into a seed, enclosing the developing embryo and endosperm. Therefore, the correct sequence is I → II → V → III → VI → IV. The final answer is A. Recap: This question tests the sequential understanding of the key events in pre-fertilisation, fertilisation, and post-fertilisation stages of sexual reproduction in flowering plants.