Which of the following is NOT a characteristic feature of the phylum Platyhelminthes?a)Bilateral symmetryb)Presence of a coelomc)Organ-level organizationd)Acoelomate body planCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

Understanding Platyhelminthes Characteristics
The phylum Platyhelminthes, commonly known as flatworms, exhibits several distinct features that define its biological classification. Among these characteristics, the presence of a coelom is NOT one of them. Here's a detailed explanation:
Key Features of Platyhelminthes
- Bilateral Symmetry:
- Platyhelminthes exhibit bilateral symmetry, meaning their body can be divided into two identical halves along a single plane. This is a characteristic feature that allows for more complex body structures and the development of a head region.
- Organ-Level Organization:
- These organisms possess an organ-level of organization, meaning that their bodies are made up of various organs that work together to perform specific functions. This complexity is more advanced than simpler organisms.
- Acoelomate Body Plan:
- Platyhelminthes are classified as acoelomate, which means that they lack a coelom (a fluid-filled body cavity). Instead, their bodies are filled with a solid mass of tissue called mesenchyme, which lies between the ectoderm and endoderm layers.
Why Presence of Coelom is Incorrect
- Absence of Coelom:
- The defining feature of Platyhelminthes is the absence of a coelom. Unlike coelomates, which have a true body cavity lined by mesoderm, flatworms have no such structure, making them distinct in this regard.
In summary, the correct answer is option 'B' because Platyhelminthes are acoelomate organisms, lacking a true coelom. This sets them apart from other phyla that do possess a coelomic cavity.

Answer

Platyhelminthes, or flatworms, are characterized by their bilateral symmetry, organ-level organization, and acoelomate body plan, meaning they do not have a coelom (body cavity). The presence of a coelom is not a feature of Platyhelminthes but rather of more advanced phyla like Annelida and Arthropoda. An interesting fact about Platyhelminthes is that despite their simple structure, some species have complex life cycles involving multiple hosts.

Answer

Characteristics of Platyhelminthes
Platyhelminthes, commonly known as flatworms, exhibit several unique characteristics that distinguish them from other animal phyla. Here’s a breakdown of their traits:
1. Bilateral Symmetry
- Platyhelminthes display bilateral symmetry, meaning their body plan is symmetrical along a single plane. This feature allows for a streamlined body structure, which is advantageous for movement.
2. Organ-Level Organization
- These organisms possess an organ-level organization, with specialized tissues forming organs that perform specific functions. This complexity enables more efficient physiological processes compared to simpler forms of life.
3. Acoelomate Body Plan
- Flatworms are classified as acoelomates, meaning they lack a true coelom (body cavity) between the digestive tract and the outer body wall. Instead, their body is filled with parenchyma, a type of tissue.
4. Absence of a Coelom
- The key distinction for this question is the presence of a coelom. Unlike coelomates (organisms with a true coelom), Platyhelminthes do not have this feature. This absence is a defining characteristic of the phylum.
Conclusion
Therefore, option 'B', which states the presence of a coelom, is NOT a characteristic feature of the phylum Platyhelminthes. This clarification helps in understanding the fundamental biological classifications and characteristics of different animal groups.

Top Courses for NEETView all

Biology Class 11

Daily Test for NEET Preparation

Topic-wise MCQ Tests for NEET

NEET Mock Test Series - Updated 2026 Pattern

Physics Class 11

Top Courses for NEET

Top Courses for NEET

Related Content

About NEET

NEET Preparation Material

How to Prepare for NEET Exam?

NCERT Based Study Material

NEET Mock Tests

Other Popular Exams

Company