Read the given paragraph and answer the given question :
Parasitism has evolved in many taxonomic groups from plants to higher vertebrates. Many parasites have evolved to be host specific in such a way that both host and the parasite tend to co-evolve. In accordance with their life styles, parasite evolve special adaptations and complex life cycle.
What are the intermediate hosts for human liver fluke?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Snail and Fish.
Option (1) Snail and Fish. — Correct. The human liver fluke, a trematode, needs both to complete its life cycle.
Option (2) Snail and fresh water mussel — Incorrect. The second intermediate host is a fish, not a mussel.
Option (3) Fish and Man — Incorrect. Man is the primary host, not an intermediate one.
Option (4) Snail and Man — Incorrect. Again man is the primary host.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Population Interactions – “… The life cycles of parasites are often complex, involving one or two intermediate hosts or vectors to facilitate parasitisation of its primary host. The human liver fluke (a trematode parasite) depends on two intermediate hosts (a snail and a fish) to complete its life cycle.”