Biology MCQs class 12 Chap 13 ( Organisms and Populations )


Multiple choice questions.

1. Which factor of an ecosystem includes
plants, animals and microorganisms?
    a. Biotic factor
    b. Abiotic factor
    c. Direct factor
    d. Indirect factor

Answer : Biotic factors



2. An assembladge of individuals of different species living in the same habitat and having functional interactions is ................
    a. Biotic community
    b. Ecological niche
    c. Population
    d. Ecosystem

Answer : A
Explanation : An association of individuals of different species living in the same habitat and having functional interactions is called a biotic community. It is also known as biocoenosis.Together the biotic and abiotic communities make up an ecosystem.



3. Association between sea anemone and Hermit crab in gastropod shell is that of ................
    a. Mutualism
    b. Commensalism
    c. Parasitism
    d. Amensalism

Answer : B
Explanation : Hermit crabs and sea anemones have a symbiotic relationship, meaning they live in harmony together. It's a stable connection that sidesteps the typical prey and predator relationship found in nature. The type of symbiosis they engage in is called commensalism.




4. Select the statement which explains best
parasitism.........
    a. One species is benefited.
    b. Both the species are benefited.
    c. One species is benefited, other is not              affected.
    d. One species is benefited, other is                     harmed.

Answer : D
Explanation : In evolutionary biology, parasitism is a symbiotic relationship between species, where one organism, the parasite, lives on or in another organism, the host, causing it some harm, and is adapted structurally to this way of life.



5. Growth of bacteria in a newlly innoculated agar plate shows ................
    a. exponential growth
    b. logistic growth
    c. Verhulst-Pearl logistic growth
    d. zero growth

Ans : Zero Growth


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