Competitive Exams: Botany MCQs (Practice-Test 32 of 104)

  1. Which one of the following is an important source of methane emission in the atmosphere?

    1. Wetlands

    2. Degraded forests

    3. Thermal power generators

    4. Wheat fields

  2. Which one of the following is the main cause of photochemical smog?

    1. Carbon dioxide acting as nuclei for water droplet formation

    2. Increase in atmosphenc carbon dioxide concentration leading to green house effect

    3. Nitrogen oxides and hydrocarbons in the air, exposed to ultra violet light

    4. Environmental conditions favoring excessive evaporation resulting in smog formation in the morning

  3. The term ‘Phytoremediation’ refers to the

    1. Use of plants for removing pollutants from the environment

    2. Use of plants as remedies to cure diseases

    3. Use of plants for restoration of degraded forests

    4. Use of plants in the retention of soil water

  4. Among the following forest types, which one has the highest net primary productivity?

    1. Tropical rain forest

    2. Tropical dry deciduous forest

    3. Subtropical forest

    4. Temperate rain forest

  5. When propagates are formed on the floral branches either in addition to or in place of flowers, the phenomenon is commonly described as

    1. Apospory

    2. Diplospory

    3. Parthenocarpy

    4. Vegetative vivipary

    • Assertion (A): Somatic cell hybridization is possible in distantly related species.
    • Reason (R): Somatic cell hybridization overcomes the barriers in natural fertilization.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true

    • Assertion (A): Excess of nitrogen if supplied to the plants is not beneficial to them.
    • Reason (R): It reduces shoot/root ratio.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true

    • Assertion (A): In a mature grain of maize, aleuronic tissue is the only living part of the endosperm.
    • Reason (R): During seed germination the embryo draws its nutrition from the aleuronic cells.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true

    • Assertion (A): In crop improvement programmes haploids are good breeding materials haploids are good breeding materials.
    • Reason (R): Haploids can be used to produce homozygous lines in one step.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true

    • Assertion (A): Plants do not have an immune system like animals but possess inducible defense mechanisms effective against diseases.
    • Reason (R): Only chemical treatment of susceptible host plants induces resistance.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true

    • Assertion (A): Overgrazing contributes to endemism in animals.
    • Reason (R): Overgrazing affects species diversity.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true

    • Assertion (A): Asexual reproduction associated with marine red algae takes place through flagellated spores.
    • Reason (R): Asexual reproduction associated with marine red algae takes place through flagellated spores.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true

    • Assertion (A): Infection of legume roots by a rhizoidal species does not always result in the development of nodules for nitrogen fixation.
    • Reason (R): In addition to the nif genes, a group of genes essential for symbiotic nitrogen fixation, designated as fix genes, are present in Rhizobium and these genes must be active for nitrogen fixation.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true

    • Assertion (A): The life cycle in Fucus is hypnotic.
    • Reason (R): The gametophyte in Fucus is greatly reduced.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true

    • Assertion (A): In plants vessels are better conductors than trachea.
    • Reason (R): Vessel elements are shorter than trncheids.
    1. Both A and R are individually true and R is the correct explanation of A

    2. Both A and R are individually true but R is not the correct explanation of A

    3. A is true but R is false

    4. A is false but R is true