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Organisms and Populations — BIOLOGY STD 12 Science — Question

Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYOrganisms and Populations1 Mark
MCQ
For question two statements are given $-$ one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : Predation and parasitism are considered to be negative interactions.
Reason : Predators and parasites limit the population of their host species.
  • ✓
    Both assertion and reason are true and reason is the correct explanation of assertion.
  • B
    Both assertion and reason are true but reason is not the correct explanation of assertion.
  • C
    Assertion is true but reason is false.
  • D
    Both assertion and reason are false.
✓

Answer

Correct option: A.
Both assertion and reason are true and reason is the correct explanation of assertion.
Predation and parasitism are considered to be negative interactions, because in both of these interactions one species gains and the other suffers.
Predation is the interaction between species involving killing and consumption of prey.
The species which eats the other is called the predator, and the one consumed by other is termed as prey. Predation is commonly illustrated by the herbivore $-$ carnivore interaction.
Parasitism is the interaction in which the species smaller in size $($the parasite$)$ lives in or on the larger species $($the host$)$ from which it obtains food and shelter. Parasites like leech es, tick, lice, mites feed on the body fluids of the hosts.
Parasites, like the predators limit the population of the host species. Parasites are generally host $-$ specific, and do not have choice or altematives like predators.
Parasites are smaller in size and have higher biotic/reproductive potential compared to the predators. Parasites have poor means of dispersal and require specialised structures to reach or invade the host. Predators, on the other hand, are quite mobile and capable of capturing the prey.

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