The kingdom Animalia comprises eukaryotic, multicellular organisms.
Photosynthetic organisms (autotrophs) possess chlorophyll pigment that helps them to synthesize their own food from inorganic substances such as CO2, H2O, and mineral in presence of sunlight.
Animals are heterotrophs. They depend on living organisms to obtain nutrition.
The green sea slug (Elysia chlorotica) is a photosynthetic animal belonging to the phylum Mollusca. They acquire chlorophyll by ingesting yellow-green algae (Vaucheria litorea), this process is known as ‘Kleptoplasty’.