Blank will develop pharyngeal arches. blank will develop a postanal tail in the embryonic stage

1st blank - earthworms, barb fish, crabs, leeches

2nd blank - ladybugs, snails, sea cucumbers, newts

Answer: 1. barb fish 2. newts

The pharyngeal arches are the structures which are precursors of embryonic development in the vertebrates. In the fishes, gill arches or branchial arches mimicking the phyrangeal arches. Among the option given, the barb fish is the relevant option for the first blank.

This type of tail development is the characteristic property of the chordates. Among the options given, the newts is the relevant one as these are chordates.

First blank is barb fish

And the second blank is newts