Question

Which of the following is an example of an animal that has a single opening that serves as mouth as well as anus?
A. Fasciola
B. Octopus
C. Asterias
D. Ascidia

Answer 1

Hint: Single opening is a characteristic of the animals with blind sac level of body organization. A single opening that acts as both mouth and anus is known as the blind sac level of body organization. It is a characteristic of the phylum Cnidaria, Ctenophora, and Platyhelminthes.

Complete answer: Blind sac organization is the body organization that consists of a single opening serving as both the mouth and the anus. It is found in phyla like Cnidaria, Ctenophora, and Platyhelminthes. Platyhelminthes are known as the flatworms. They are dorsoventrally flat animals. They have a blind sac level of organization where a single opening acts as mouth and anus both. Platyhelminthes are triploblastic, acoelomate animals. This means that they have three germinal layers but no coelom present.

-Fasciola is a member of the phylum Platyhelminthes. They are commonly known as Flatworms. The members of the Platyhelminthes phylum have a blind sac body organization. In a blind sac body organization, a single opening in the body acts as both mouth and anus.
-Octopus is a member of the phylum Mollusca. They are soft-bodied animals. The members of the Mollusca phylum have a tube within a tube body organization. In a tube within a tube organization, there is a complete alimentary canal present, with two different openings in the body that act as mouth and anus respectively.
-Asterias is a member of the phylum Echinodermata. They are spiny-armed animals. The members of the echinodermata phylum have a tube within a tube body organization. In a tube within a tube organization, there is a complete alimentary canal present, with two different openings in the body that act as mouth and anus respectively.
-Ascidia is a member of the phylum Chordata. They are the animals with a tunicin cover. The members of the chordata phylum have a tube within a tube body organization. In a tube within a tube organization, there is a complete alimentary canal present, with two different openings in the body that act as mouth and anus respectively.
Thus, based on the above information, we can conclude that Fasciola is an example of an animal that has a single opening that serves as a mouth as well as anus.
Hence, the correct answer is option (A).

Note: Fasciola also known as Fasciola hepatica is commonly known as the liver fluke. This is because they are mainly the parasites of the liver. They are found in the liver of several mammals including humans. They can move along the blood circulation and via that they reach several organs of the body.