The diagram below shows stages in the life cycle of a parasite. Study it and answer question 20. Which of the following organisms serves as host to the para...

The diagram below shows stages in the life cycle of a parasite. Study it and answer question 20. 

Which of the following organisms serves as host to the parasite at the stage labelled I and II respectively ?

Answer Details

At stage I, the parasite is in the form of eggs, which are released from the human host through feces. These eggs hatch into larvae in water and the larvae then infect snails, where they undergo further development. At stage II, the parasite leaves the snail and forms cysts on vegetation. The cysts are ingested by pigs when they eat the vegetation, and the parasite develops further in the pig's body. Therefore, the organism that serves as a host to the parasite at stage I is the human, and at stage II it is the pig. The correct option is "Human, pig".