Well-defined nucleus is absent in

To which class of Animalia does the housefly belong? Mention any three characteristic features of this class of animals. Give two other examples of this class of animals.

Match items of column $(A)$ with items of column $(B)$:

Column $(A)$	Column $(B)$
$(a)$ Naked seed	$(A)$ Angiosperms
$(b)$ Covered seed	$(B)$ Gymnosperms
$(c)$ Flagella	$(C)$ Bryophytes
$(d)$ Marchantia	$(D)$ Euglena
$(e)$ Marsilea	$(E)$ Thallophyta
$(f)$ Cladophora	$(F)$ Pteridophyta
$(g)$ Penicillium	$(G)$ Fungi

Differentiate between the following:
$(a)$ Tube system of feather star and canal system of $Euplectella$
$(b)$ Skeleton of shark and sea horse
$(c)$ Respiratory organs of tadpole and frog
$(d)$ Forelimbs of birds and lizard
$(e)$ Skin of tree frog and human

Who proposed the two kingdom classification?

Which of the following features is not a characteristic of $Protochordata$?