Question

feathers of birds are made up of an insoluble protein called ​

Answer 1

Answer:

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Keratin is found in both animals and birds. So the answer is Keratin. Biotin is also an insoluble pigment found in bird's feathers, but it is not a protein.

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Answer 2

Keratin is found in both animals and birds. So the answer is Keratin. Biotin is also an insoluble pigment found in bird's feathers, but it is not a protein

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