What Is Protista?

It includes all unicellular eukaryotes organisms such as diatom, ciliates, slime moulds, sporozoans etc. They have different types of nutrition. They live in sea and form plankton which may be photosynthetic known as Phytoplankton. In contrast the plankton which are non photosynthetic are known as Zooplankton. Nuclear material is organized. DNA is covered. The presence of flagella is suspected. Sexual methods of reproduction are present. It also includes the main organelles such as mitochondria, lysosomes, plastids. There are organisms which have double mode of nutrition such as euglena. Cellular organization is double envelope.