Question

1. two interactions between organisms are shown in the table below. x and y do not represent the same organisms in the two interactions

	organism x	organism y
interaction 2	parasite	host

which statement best describes the relationship between organism x and organism y in each interaction? (1) organism x is positively affected by the relationship and organism y is negatively affected (2) organism x is negatively affected by the relationship and organism y is positively affected (3) both organisms are positively affected by the relationship (4) both organisms are negatively affected by the relationship

1. after the aswan high dam was built on the nile river, the rate of parasitic blood - fluke (a worm - like microorganism) infection doubled in the human population near the dam. as a result of building the dam, the flow of the nile changed. this changed the habitat, which resulted in an increase in its population of a certain aquatic snail. the snails, which were infected, released larvae of the fluke. these larvae then infected humans. the role of the snail in this relationship may be described as a

Explanation:

1.

In a predator - prey relationship, the predator benefits by getting food (positively affected) and the prey is harmed (negatively affected). In a parasite - host relationship, the parasite benefits by living off the host and the host is harmed. So organism X (predator/parasite) is positively affected and organism Y (prey/host) is negatively affected.

The snail is infected by the fluke and releases its larvae which infect humans. In a parasite - host relationship, the infected snail serves as a host for the fluke.

Answer:

(1) Organism X is positively affected by the relationship and organism Y is negatively affected

2.