State whether the following statement is true or false:
$Platyhelminthes$ are either free-living or parasitic.

Which of the following is not a characteristic feature of Protochordata?

The skeleton is made entirely of cartilage in

Amphibians do not have the following:

Enlist four main features of organisms placed in the kingdom Protista.

$X, Y$ and $Z$ are living organisms.
$(a)$ Identify the group to which they belong on the basis of following features:
$(i)$ $X -$ Microscopic,unicellular,prokaryotic.
$(ii)$ $Y -$ Microscopic,unicellular,eukaryotic and shows locomotion with the help of pseudopodia/flagella.
$(iii)$ $Z -$ Multicellular,filamentous,eukaryotic,autotrophic and aquatic.
$(b)$ Which amongst the above is most advanced?
$(c)$ Name one organism each belonging to the groups of $X, Y$ and $Z$.