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Human Health and Disease — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYHuman Health and Disease1 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 : Spleen can be thought of as an immunologic conference centre.
Reason: Spleen helps only in digestion.
✓

Answer

  1. Assertion is true, but reason is false.

Explanation:

The spleen is an immunologic filter of blood. It is made up of B-cells, T-cells, macrophages, dendritic cells, natural killer cells and red-blood cells. In addition to capturing foreign materials (antigens) from the blood that passes through the spleen, migratory macrophages and dendritic cells bring antigens to the spleen via blood stream. An immune response is initiated when the macrophages or dendritic cells present the antigen to the appropriate B or T-cells. This organ can be thought of as an immunological conference centre. In the spleen, B-cells become activated and produce large amounts of antibody.

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