B because Phasmids are chemoreceptors that open one on either side of tail of female Ascaris.

Phasmids of Ascaris are Chemoreceptors

Chemoreceptors are sensory receptors that respond to chemical stimuli in the environment. They are responsible for detecting and responding to specific chemicals or chemical changes in the surroundings. In the case of Ascaris, a parasitic roundworm, the phasmids are chemoreceptors.

What are Phasmids?

Phasmids are specialized structures found in the posterior end of the body of Ascaris worms. They are paired structures located on either side of the anus. These structures contain clusters of chemoreceptor cells that are sensitive to chemical cues in the environment.

Role of Phasmids in Ascaris

The primary function of phasmids in Ascaris is to detect and respond to chemical signals related to their environment. Ascaris worms are parasites that live in the intestines of animals, including humans. They rely on chemical cues to find suitable hosts, locate food sources, and avoid unfavorable conditions.

Chemical Detection and Response

Ascaris worms use their chemoreceptors to detect various chemicals, including those released by their hosts or by nearby food sources. These chemoreceptors are sensitive to specific molecules or chemical gradients in the environment. When a chemical stimulus is detected, the chemoreceptor cells in the phasmids generate electrical signals that are transmitted to the nervous system of the worm.

Behavioral Responses

The chemical signals detected by the phasmids play a crucial role in guiding the behavior of Ascaris worms. For example, if the worm detects chemical cues indicating the presence of a suitable host, it may move towards the source of the chemicals. On the other hand, if the worm detects chemical cues associated with an unfavorable environment or potential threats, it may exhibit avoidance behavior and move away from the source of the chemicals.

Conclusion

In conclusion, the phasmids of Ascaris are chemoreceptors that play a vital role in detecting and responding to chemical signals in the environment. These sensory structures help the worms navigate their surroundings, find hosts, locate food sources, and avoid potential dangers.