(b) What is a ‘vaccine’? Explain the principle on which it works.
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Solution and Explanation
- Definition: A vaccine is a biological preparation that provides active immunity against specific diseases.
- Principle: Vaccines work by stimulating the immune system to produce antibodies against the disease-causing agent without causing the disease itself. This enables the body to fight the actual pathogen in the future.
Top Questions on Immunity
- The foetus receives some antibodies from their mother through the placenta during pregnancy. Choose the correct option that shows the type of immunity developed in the foetus.
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- CUET (UG) - 2023
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Questions Asked in CBSE CLASS XII exam
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- Electromagnetic induction
A racing track is built around an elliptical ground whose equation is given by \[ 9x^2 + 16y^2 = 144 \] The width of the track is \(3\) m as shown. Based on the given information answer the following:
(i) Express \(y\) as a function of \(x\) from the given equation of ellipse.
(ii) Integrate the function obtained in (i) with respect to \(x\).
(iii)(a) Find the area of the region enclosed within the elliptical ground excluding the track using integration.
OR
(iii)(b) Write the coordinates of the points \(P\) and \(Q\) where the outer edge of the track cuts \(x\)-axis and \(y\)-axis in first quadrant and find the area of triangle formed by points \(P,O,Q\).
- CBSE CLASS XII - 2026
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- The painting Hazrat Nizamuddin Auliya and Amir Khusro belongs to which sub-school of Deccan Miniature?
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