Absence of Coelosepta in Earthworm

Coelosepta are transverse partitions or septa that divide the segments of an earthworm's body. These septa play an important role in maintaining the integrity and function of the coelom, which is the fluid-filled body cavity in earthworms. However, Coelosepta are absent in certain segments of an earthworm's body. Let's explore the correct answer in detail.

I. Explanation of the Answer

The correct answer to the question "Coelosepta are absent in earthworm" is option 'D', which states that they are absent in both the 2nd and 3rd segments of an earthworm. This means that Coelosepta are not present in these specific segments.

II. Earthworm Segmentation

Earthworms are segmented organisms, and their bodies are divided into a series of repeating segments. Each segment contains specific structures and functions that contribute to the overall physiology of the earthworm. The segments are numbered sequentially from anterior (head) to posterior (tail) end.

III. Distribution of Coelosepta

Coelosepta are present in most of the segments of an earthworm's body, but they are absent in certain segments. The distribution of Coelosepta can vary depending on the species of earthworm. In the case of the earthworm species mentioned in the question, the Coelosepta are absent in both the 2nd and 3rd segments.

IV. Significance of Coelosepta

Coelosepta are important structures as they help in maintaining the integrity of the coelom and provide support to the internal organs. They also facilitate movement and locomotion by acting as anchor points for the muscles that control the earthworm's body movements. Additionally, these septa play a role in the circulation of fluids within the coelom, enabling nutrient transport and waste removal.

V. Importance of Earthworm Segmentation

Earthworm segmentation is crucial for their survival and functions. Each segment contains a set of organs and structures that have specific roles. The segments work together in a coordinated manner to carry out essential biological processes such as digestion, respiration, reproduction, and locomotion. The absence of Coelosepta in certain segments does not disrupt the overall functionality of the earthworm's body.

In conclusion, Coelosepta are absent in both the 2nd and 3rd segments of an earthworm's body. While these structures are present in most other segments, their absence in these specific segments does not hinder the overall functionality of the earthworm. The remaining segments still contain the necessary organs and structures to carry out vital biological processes.

Answer is [b] septa absent in 1st four segments