Theory:

Make a cross section of any fruit in your house
(Or)
Make a longitudinal section of any vegetable in your house and observe.
 
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What did you observe in the fruits and vegetables?

After fertilization the flowers transform into a fruit.
 
The following are the observations one could make:
 
After the fertilization when the flower grows,
  • Calyx may sometimes stick to the fruit.
  • Petals mostly drop when the flower becomes fruit.
  • Pistil becomes a fruit.
  • Style/stigma and androecium drop off.
  • After fertilization the ovary grows and store more food material and becomes a fruit.
  • The ovules become seeds.
  • The number of seeds corresponds to the number of ovules in the ovary.
Important!
Do you know?
One of the rare and globally threatened species of palm, the double coconut (Lodoicea maldivica) tree was planted at the botanical garden in 1894 and the artificial pollination is a result of decades of work by scientists of the Botanical Survey of India (BSI).**
Reference:
** - Article from The Hindu - https://www.thehindu.com/news/national/indias-only-double-coconut-tree-artificially-pollinated/article7310257.ece#:~:text=One%20of%20the%20rare%20and,Survey%20of%20India%20(BSI).