Physics
Holography is a technique of

Recording a permanent, sharp two diimensional black and white or multicolour photograph
Recording a permanent three dimensional multicolour photograph
Recording a permanent three dimensional photograph of a given single colour or a multicolour
Recording a permanent three dimensional black and white photograph

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Physics
Planets do not twinkle because

They are very far away from the earth resulting in decrease in intensity of light
Their distance from the earth does not change with time
They emit light of a constant intensity
They are nearer to earth and hence we receive a greater amount of light.

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