The kingdom that includes both autotrophic and heterotrophic unicellular and multicellular organisms is the Kingdom Protista.
Protists are a diverse group of eukaryotic microorganisms. They can be unicellular or multicellular and exhibit a wide range of nutritional modes. Some protists, like algae, are autotrophic and can perform photosynthesis to produce their own food. Others, like amoebas and paramecia, are heterotrophic and obtain their nutrients by consuming other organisms or organic matter.
This kingdom is unique because it encompasses a variety of life forms that do not fit neatly into the other traditional kingdoms (Animalia, Plantae, Fungi, and Monera). Protists play crucial roles in ecosystems, particularly in aquatic environments, where they contribute to the food web and oxygen production.