Which of the following is a post-fertilisation event in flowering plants?

1. Transfer of pollen grains

2. Embryo development

3. Formation of flower

4. Formation of pollen grains

(b)
Embryo development takes place after the fertilisation, i.e., fusion of male and female gametes (n) result in the formation of zygote (2n). Thus, it is a post fertilisation event.

Rest of the events takes place before occurrence of fertilisation, hence are pre fertilisation events.