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Organisms and Populations — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYOrganisms and Populations1 Mark
Question
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.
  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
  3. Assertion is true but reason is false.
  4. Both assertion and reason are false.
Assertion: Many plants growing in oli gotroph ic soi Is possess mycorrhizae.
Reason: Mycorrhizae help in efficient absorption of nutrients.
✓

Answer

  1. Both assertion and reason are true and reason is the correct explanation of assertion.

Explanation:

The oligotrophic soils contain low amounts of nutrients. These soils generally develop in old and geologically stable areas, such as soils found in much of the tropical rain forest region. Due to intense weathering and high rates of leaching, these soils have a poor nutrient retention capacity. Many plants growing in nutrient-poor soils possess mycorrhizae which have mutualistic association of roots with fungi ("fungus root"). Mycorrhizae help in efficient absorption of nutrients (e.g., phosphorus). Mycorrhizae are of two types endomycorrhi zae and ectomycorrhizae. In endomycorrhizae, the fungal hyphae dwell inside roots. These types of mycorrhizae are found in many vascular plants. In ectomycorrhizae, the fungal mycelium forms a mat outside the root. Ectomycorrhizae occur in several tree and shrub species in temperate regions.

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