Where are seeds of gymnosperms formed?

Differentiation in segmental fashion occurs in

Give one example of each:
$(a)$ Reptile which has a four-chambered heart.
$(b)$ Egg-laying mammal.
$(c)$ Parasitic Platyhelminthes.
$(d)$ Division among plants which has the simplest organisms.

Write true or false for the following statement:
Plants with well-differentiated reproductive tissues that ultimately make seeds are called pteridophytes.

Hard calcium carbonate structures are used as a skeleton by

Amphibians do not have the following: