Which one of the following is not a living fossil?

$A$ larval stage occurs in the life history of all members of the group:

Which of the following sets of animals is correctly matched with its respective phylum/class?

Which one of the following occurs in molluscs but not in echinoderms?

Identify the type of digestive system in the organisms shown below.

Consider the following features:
$(a)$ Organ system level of organisation
$(b)$ Bilateral symmetry
$(c)$ True coelomates with segmentation of body
Select the correct option of animal groups which possess all the above characteristics.