When freshwater protozoans possessing contractile vacuoles are placed in a beaker containing seawater,the vacuoles will:

"Golden algae" is the common name for algae that belong to ............ .

Which of the following organisms are known as chief producers in the oceans?

Which of the following organisms exhibits holophytic (plant-like) nutrition?

The given statements are some characters of a particular group of Kingdom $Protista$.
$(i)$ Most of them are freshwater organisms found in standing water.
$(ii)$ They have a protein-rich layer (called pellicle) which makes their body flexible.
$(iii)$ They have two flagella,a short and a long one.
$(iv)$ Though they are photosynthetic in the presence of sunlight,but in the absence of sunlight they behave like heterotrophs by predating on other smaller organisms.
Identify the correct group on the basis of these characters.

Explain the main features of protozoans and their groups.