Theory:

What is sexual reproduction?
The process in which a male and a female gamete fuse to produce offspring of their own kind is known as sexual reproduction.
787px-Sexual_cycle.svg.png
Sexual reproduction
  
In this type of reproduction, both sexes, male and female sex organs, are needed to produce gametes.
The sexual reproduction of plants can be categorized into three different stages such as,
  1. Pre-fertilization events
  2. Fertilization
  3. Post-fertilization events
Sexual Reproduction Events 1x.png
1. Pre-fertilization events:
These include
  • The reproductive organs of a flower
  • Gametogenesis
  • Pollination
In our previous grade we have already learnt that the reproductive organ of angiosperms (flowering plants) is flower.
Parts of a Typical Flower:
A modified shoot with limited growth to carry out sexual reproduction is known as a flower.
A typical flower consists of four whorls borne on a thalamus.
 
Figure_26_03_02.jpg
Parts of a flower
  
The four whorls from outside are a follows:
  1. Calyx: Consisting of sepals
  2. Corolla: Consisting of petals
  3. Androecium: Consisting of stamens
  4. Gynoecium or pistil: Consisting of carpels
Reference:
https://commons.wikimedia.org/wiki/File:Sexual_cycle.svg
https://commons.wikimedia.org/wiki/File:Figure_26_03_02.jpg