What characteristics must all animals have in order to be part of the Kingdom?

What characteristics must all plants have in order to be part of the Kingdom?
What characteristics must all fungi have in order to be part of the Kingdom?
What characteristics must all protists have in order to be part of the Kingdom?
What characteristics must all bacteria have in order to be part of the Kingdom?

1 answer

All animals must be multicellular, heterotrophic, and have the ability to move (at least at some point in their life cycle) in order to be part of the Kingdom Animalia.

All plants must be multicellular, autotrophic (able to produce their own food through photosynthesis), and have cell walls made of cellulose in order to be part of the Kingdom Plantae.

All fungi must be multicellular (with the exception of some single-celled yeast species), heterotrophic (they obtain nutrients by absorption), and have chitin in their cell walls in order to be part of the Kingdom Fungi.

All protists are unicellular or multicellular organisms that are eukaryotic (have a nucleus and membrane-bound organelles), but do not fit into the categories of animals, plants, or fungi. They can be heterotrophic or autotrophic and can have a wide range of characteristics, so there is no single set of characteristics that all protists must have.

All bacteria are unicellular prokaryotic organisms (they lack a nucleus and other membrane-bound organelles) that are typically microscopic in size. They can be classified into different groups based on their shape, the way they obtain energy, and the chemical composition of their cell walls, but there is no single set of characteristics that all bacteria must have.