Meena and Hari observed an animal in their garden. Hari called it an insect while Meena said it was an earthworm. Choose the character from the following which confirms that it is an insect.

Identify a member of the phylum Porifera.

$(i)$ To which division of Plantae do algae belong? Write one characteristic of the division. Give two examples.
$(ii)$ Name the group:
$(a)$ Which includes unicellular eukaryotic organisms.
$(b)$ In which the mode of nutrition is saprophytic.
$(c)$ In which seeds are not enclosed in fruit.
$(iii)$ Classify flowering plants on the basis of the number of cotyledons present in the seed.

Define the following terms and give one example of each:
$(a)$ Bilateral symmetry
$(b)$ Coelom
$(c)$ Triploblastic

State reasons for the following:
$(a)$ Tapeworm does not have a digestive tract.
$(b)$ Frogs use both skin and lungs for breathing.
$(c)$ Birds have pneumatic/hollow bones.

Give the points of differences between non-chordates and chordates.