Which kingdom contains ONLY autotrophs?

The kingdom that contains ONLY autotrophs is Plantae.

Explanation: Autotrophs are organisms that can produce their own food through photosynthesis or chemosynthesis. The Plantae kingdom is made up exclusively of plants, which are autotrophic because they perform photosynthesis. Other kingdoms listed, such as Animalia and Fungi, contain heterotrophs, which cannot produce their own food. Archaebacteria and Eubacteria can be both autotrophic and heterotrophic, while Protista includes both types as well.

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