Animal Kingdom Question 70
Assertion : Survival of F. hepatica outside the host’s body is not so easy. Reason : Encysted body cannot survive outside the host body irrespective of the environment.
Options:
A) If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B) If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C) If the assertion is true but the reason is false
D) If both the assertion and reason are true
Show Answer
Answer:
Correct Answer: C
Solution:
Due to complicated and prolonged life cycle, development stages have to encounter several hazards.
First hazard is faced by encapsulated embryos as soon as they come out with faeces of primary host.
They cannot develop further if water (or moisture), suitable substrate, and temperature are not available.
Second hazard is encountered by miracidia which emerge from the capsules.
If they are unable to make contact with a suitable soft part of the specific intermediate host within 24 hours, they perish.
Cercariae which leave the intermediate host and swim into surrounding water are the next to face an uncertain future.
If ingested by the vertebrate host, before they have encysted, they are destroyed by the action of hosts gastric juice.
Finally, metacercariae are destroyed if they have to face a long period of dessication before they are ingested by a suitable vertebrate host.
BETA
