Why are plants classified as autotrophs?

According to the way of feeding, all living organisms are divided into autotrophs and heterotrophs.
Autotrophs are organisms that prepare organic substances for themselves from inorganic ones.
Heterotrophs use the energy of ready-made organic substances, getting them together with food. In this case, energy is transferred from organism to organism through food chains.
Plants, using the energy of the sun, from water and carbon dioxide, synthesize organic substances in cells with chlorophyll. That is why plants are autotrophic organisms.