Which among the following produce seeds?

Identify the phylum for the following characteristics given:
$(a)$ Organisms with jointed appendages.
$(b)$ Organisms are generally flatworms.
$(c)$ Body is segmented.
$(d)$ Skin of organisms is full of spikes.

Identify a member of the phylum Porifera.

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.

The locomotory organs of $Echinodermata$ are:

Which one is the most striking or common character of the vertebrates?