Question

The following features belong to which phylum? (1) Bilateral symmetry (2) Triploblastic, acoelomate (3) Organ level of organization (4) Dorsoventrally flattened body

• A. Aschelminthes
• B. Platyhelminthes
• C. Arthropoda
• D. Annelida

Answer 1

The correct option is B

Platyhelminthes

The correct option is B.

Explanation of correct option:

1. Platyhelminthes are commonly called flatworms as they have a dorso-ventrally flattened body.
2. They are triploblastic, bilaterally symmetrical and acoelomate animals.
3. They are capable of reproducing both sexually and asexually and exhibit many parasitic forms.

Explanation of incorrect options:

Option A:

1. Aschelminthes are also bilaterally symmetrical and triploblastic animals. But, they are not dorso-ventrally flattened.
2. They are commonly called roundworms because their bodies are round when examined transverse cross section-wise.

Option C:

1. Arthropoda are also bilaterally symmetrical and triploblastic animals. But their body is segmented into the head, thorax, and abdomen.
2. They include centipedes, crab, lobster, spider, cockroach, ants, butterfly, mosquito etc.

Option D:

1. Annelids are also bilaterally symmetrical, with an elongated cylindrical body divided by regular, linear series of segments.
2. They include earthworm, polychaetes, leeches etc.

Final Answer: So, Platyhelminthes have organ level of organization and dorsoventrally flattened body and are bilaterally symmetrical, triploblastic, acoelomate.