Where are seeds of gymnosperms formed?

Which one is a true fish?

Give reasons:
$(a)$ Animals of phylum Platyhelminthes are called flatworms.
$(b)$ Bryophytes are called amphibians of the plant kingdom.
$(c)$ Fungi are called saprophytes.
$(d)$ Bacteria and tapeworms are very different in their body design.
$(e)$ Plants like Pinus and deodar are called gymnosperms.

Give reasons for the following:
$(a)$ Echidna and Platypus lay eggs but are considered as mammals.
$(b)$ Birds have pneumatic bones.

The skeleton is made entirely of cartilage in

State the reason for the following:
$(i)$ Nematodes have a pseudocoelom.
$(ii)$ Arthropods have an open circulatory system.
$(iii)$ Echinoderms are named as such.