How does the relationship between a snail and a parasitic worm exemplify parasitism in ecology?

• A. Neither the snail nor the worm is affected by their interaction.
• B. Both the snail and the worm benefit equally from their association.
• C. The worm benefits by living inside the snail and obtaining nutrients, while the snail is harmed by the worm's presence.
• D. The snail benefits by feeding on the worm, which is killed in the process.

Answer: (C)

Verified step by step guidance

1. Understand the concept of parasitism: Parasitism is a type of symbiotic relationship in which one organism (the parasite) benefits at the expense of the other organism (the host), which is harmed.
2. Analyze the relationship described: In this case, the parasitic worm lives inside the snail and obtains nutrients from it. This benefits the worm but harms the snail, as the snail loses resources and may suffer damage to its health.
3. Eliminate incorrect options: The first option ('Neither the snail nor the worm is affected') describes a neutral relationship, not parasitism. The second option ('Both the snail and the worm benefit equally') describes mutualism, not parasitism. The fourth option ('The snail benefits by feeding on the worm') describes predation, not parasitism.
4. Identify the correct option: The correct answer is the one that states 'The worm benefits by living inside the snail and obtaining nutrients, while the snail is harmed by the worm's presence,' as this aligns with the definition of parasitism.
5. Conclude by reinforcing the concept: Parasitism is characterized by one organism benefiting (the parasite) while the other is harmed (the host), as exemplified by the relationship between the snail and the parasitic worm.