Classify the following organisms based on the absence/presence of a true coelom (i.e., acoelomate, pseudocoelomate, and coelomate): $Spongilla$, $Sea \text{ } anemone$, $Planaria$, $Liver \text{ } fluke$, $Wuchereria$, $Ascaris$, $Nereis$, $Earthworm$, $Scorpion$, $Birds$, $Fishes$, $Horse$.

Which one is a true fish?

Pteridophyta do not have

$X, Y$ 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 $Z$.

Find out the incorrect sentence.

Name an organism sensitive to $SO_{2}$ in air.