Animalia Questions in English

(C) $Fasciola \ hepatica$ is commonly known as the Liver fluke,which belongs to the phylum Platyhelminthes.
$Taenia \ solium$ is commonly known as the Pork tapeworm,which also belongs to the phylum Platyhelminthes.
Therefore,the correct pair is Liver fluke and Tapeworm.

(D) The body cavity is a fluid-filled space between the body wall and the digestive tract.
Based on the presence or absence of a body cavity (coelom), animals are classified as acoelomates, pseudocoelomates, or coelomates.
$1$. $Platyhelminthes$ are acoelomates (no body cavity).
$2$. $Nematoda$ (roundworms) are pseudocoelomates, meaning they possess a false body cavity where the mesoderm is present as scattered pouches between the ectoderm and endoderm.
$3$. $Annelida$ and $Arthropoda$ are true coelomates (possess a true body cavity lined by mesoderm).
Therefore, the correct phylum is $Nematoda$.

(A) Insects belong to the Phylum $Arthropoda$. The most distinct and diagnostic characteristic of $Arthropoda$ is the presence of jointed appendages (jointed legs).
Earthworms belong to the Phylum $Annelida$,which are characterized by a segmented,cylindrical body but lack jointed legs.
Bilateral symmetry is found in both $Arthropoda$ and $Annelida$,so it cannot be used to distinguish them.
Therefore,the presence of jointed legs confirms that the animal is an insect.

(A) The statement is True.
$Platyhelminthes$,commonly known as flatworms,exhibit diverse lifestyles.
Many species are parasitic,such as $Taenia$ (tapeworm) and $Fasciola$ (liver fluke),which live inside the bodies of other animals.
However,some species are free-living,such as $Planaria$,which are found in freshwater or marine environments.

(TRUE) The statement is True.
Animals in the phylum Nematoda (also known as Nemathelminthes or roundworms) exhibit a tissue-organ level of body organization. While they possess a complete digestive tract (a significant evolutionary advancement),they lack complex,specialized organ systems found in higher phyla. Therefore,they are generally described as having a tissue-organ level of organization rather than a complex organ-system level.

(B) False.
The statement is false because the water-driven tube system,known as the water vascular system,is a characteristic feature of phylum $Echinodermata$,not $Mollusca$.
Animals in phylum $Mollusca$ typically use a muscular foot for locomotion.