Hint: In Spite of differences in structure and form of different animals, there are fundamental features common to various individuals in relation to the arrangement of cells, body symmetry, nature of coelom, pattern of digestive, circulatory or reproductive systems.
Different features are used as the basis of animal classification and some of them are discussed here.
-Porifera: They are organisms which have pores in their body. For example, sycon.
-Coelenterates: They are organisms that contain cnidoblast. For example, hydra.
-Ctenophores: They are commonly known as comb jellies. For example, ctenoplana
-Platyhelminthes: They are flatworms. For example – tapeworm
-Aschelminthes: They are roundworms. For example – ascaris
-Annelida: the segmentation of the body is first seen here. For example – earthworm
-Arthropods: it is the largest phylum. The body consists of the head, thorax and abdomen.
-Mollusca: this is the second largest phylum. For example, octopus.
-Echinodermata: they are spiny skinned organisms. For example, star fish.
Now let us find solution from given options:
A) Frog-External ears: Frogs do not possess external ears. Rather they have an eardrum of sorts, called a tympanum, which is located just behind each eye.
B) Earthworm - Muscular gizzard, typhlosole: Typhlosole are defined as internal folds of the intestine or intestinal inner wall. Typhlosole is present in bivalve molluscs, lampreys and some annelids including earthworms and echinoderms. Muscular gizzard is present in the digestive tract of earthworms.
C) Human - Fat globule, 10 pairs of cranial nerves: in humans 12 pairs of cranial nerves are present.
D) Cockroach Chilopoda: Chilopoda is a class of the kingdom Mollusca but cockroaches belong to the phylum Annelida.
Hence the correct answer is option ‘B’ i.e, Earthworm - Muscular gizzard, typhlosole.
Note: The gizzard, is also termed as the ventriculus, gastric mill, and gigerium, is an organ that occurs in the digestive tract of some animals, including birds, reptiles, earthworms and some fish. This specialized organ constructed of thick, muscular walls functions for grinding up food; often rocks are instrumental in this process. In some of the insects and molluscs, the gizzard features chitinous plates or teeth.