Question

In which of the following phylum has only a single opening to outside of the body that serve as both mouth and anus, and also triploblastic condition?
(a) Coelenterata
(b) Platyhelminthes
(c) Aschelmimthes
(d) Ctenophora

Answer 1

Answer:

Phylum Platyhelminthes has single opening to outside of the body that serve as both mouth and anus with triploblastic condition.

Explanation:

The following are some of the most essential properties of Platyhelminthes:

• They could be parasitic or free-living.
• The body is covered in a soft covering that may or may not have cilia.
• Their body is flattened dorsoventrally without any segmentation and resembles a leaf.
• They lack the anus and circulatory system, although they do have a mouth.
• They breathe by simply diffusing oxygen via their skin.
• They are organised at the organ level.
• They are unable to digest food because they lack a digestive tract.
• Connective tissue parenchyma fills the space between the body wall and the organs, which aids in the transfer of food.
• They are hermaphrodites, meaning they have both male and female organs in the same body.
• They reproduce sexually through the union of gametes and spermatozoa.

Answer 2

Answer:

The correct answer to the question which phylum has a single opening outside of the body which serves as both mouth and anus, and triploblastic condition is b) Platyhelminthes.

Explanation:

• Platyhelminthes or flatworms contain animals which have an incomplete digestive tract as they have a single opening which acts as both the mouth and the excretory opening anus.
• Platyhelminthes contain tapeworms like Taenia solium.
• They are triploblastic, i.e, they contain all the three germ layers (epiderm, mesoderm and endoderm)
• The mesodermal tissues give them the characteristic contractile ability which allows them to move.
• Coelenterata and Ctenphora also possess a single digestive opening but they are diploblastic.
• Aschelminthes or round worms or Nematodes contain two separate openings for mouth and anus (complete digestive tract) and are triploblastic.

Thus, the animal phylum containing a single digestive opening and triploblastic body wall is Platyhelminthes.