Question

Meena and Hari observed an animal in their garden. Hari called it an insect while Meena said it was an earthworm. Choose the character from the following which confirms that it is an insect.
(a)Body rounded
(b)Body with jointed legs
(c)Cylindrical body
(d)Body soft and unsegmented

Answer 1

Insects belong to the phylum Arthropoda which is the largest phylum of animals. In arthropods, insects make up to 75%. There are many characteristic features of arthropods like the presence of a chitinous exoskeleton, division of the body into the head, thorax, and abdomen, etc.

Complete answer:
The character that confirms that the following animal is an insect is the presence of a body with jointed legs. This is because insects belong to Arthropoda and the name arthron means ‘joint’ and poda means ‘feet’. Thus the most distinguishing feature of arthropods is the presence of jointed legs. Whereas earthworm belongs to the phylum Annelida which means little rings present all over the body. Thus, the characteristic feature of annelids is the presence of little rings which are known as metameres.

Additional Information: Let us know more about the phylums Arthropoda and Annelida.
Arthropoda:
-It is the largest phylum of animals with over two-thirds of all named species in its group.
-Arthropods have an organ-system level of organization and are bilaterally symmetrical, triploblastic, and coelomate animals.
-Respiration occurs through gills, book gills, book lungs, or tracheal systems.
-Circulatory system present in them is of open type and excretion is through Malpighian tubules.
Examples include Apis (honey bee), Bombyx (silkworm), Locusta (locusts), Limulus (king crab).
Annelida:
-They are found as both aquatic and terrestrial animals which may be free-living as well as parasitic.
-They exhibit an organ-system level of organization and are triploblastic, bilaterally symmetrical coelomate animals.
-Their body is clearly divided into segments of metameres and this phenomenon is known as metamerism.
-They have a closed circulatory system and nephridia helps in excretion.
-Examples include Nereis , Pheretima (earthworm), and Hirudinaria (leech)
So, the correct option is ‘Body with jointed legs’.

Note: -The second-largest animal phylum is the group Mollusca.
-Limulus is also a living fossil.
-Nereis is an aquatic annelid and it is dioecious in nature.