Protista is a heterogeneous group of eukaryotic organisms. Their nucleus is surrounded by a nuclear envelope, and they have organised plastids and mitochondria in them. Most of the protists are unicellular, but there are some relatively simpler multicellular forms. This group is extremely diverse, and it includes such organisms as algae, slime, moulds, and protozoa. They include both autotrophic and heterotrophic forms.
Reproduction is of both types of sexual (in some few forms) and asexual. Locomotion is by pseudopodia, or by flagella or cilia which show the typical 9+2 microtubular arrangement in them.
The members are subdivided as follows:
Plant-like protists which include Chrysophyta, Pyrophyta, Euglenophyta
Animal-like protists, which include Sporozoa, Zooflagellata, Mastigophora, Ciliata, etc.
Fungus-like protists, which are called slime moulds or Myxomycota.