Explain post-fertilization events.

(N/A) Post-fertilization events are the events in sexual reproduction that occur after the formation of the zygote.
$1$. Zygote formation: In organisms like fungi and algae,the zygote develops a thick wall that is resistant to damage and desiccation,allowing it to undergo a period of rest before germination.
The further development of the zygote depends on the life cycle of the organism and the environment in which it survives.
In all sexually reproducing organisms,a diploid zygote is formed as a result of fertilization,which eventually develops into a new organism.
$2$. Embryogenesis: The process of development of an embryo from the zygote is called embryogenesis. This process involves cell division (mitosis) and cell differentiation.
Cell division increases the number of cells,while cell differentiation helps these cells undergo modifications to form specialized tissues and organs,leading to a fully developed organism.
Depending on whether the zygote develops inside or outside the body of the female parent,animals are classified as oviparous or viviparous.
Oviparous animals (e.g.,amphibians,fishes,birds,reptiles) lay eggs that develop into new organisms. In many oviparous animals like birds and reptiles,the fertilized eggs are covered by a hard calcareous shell (cleidoic eggs).
Viviparous animals (e.g.,mammals) give birth to their young ones.
$3$. Post-fertilization changes in flowering plants: The zygote is formed inside the ovule. After fertilization,the sepals,petals,and stamens of the flower usually wither and fall off.
The zygote develops into the embryo,the ovules develop into seeds,and the ovary develops into the fruit.
The ovary wall develops into a protective layer called the pericarp.