Question

As stubborn as .........
.

don't use internet

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Answer 1

as stubborn as a mule is the answer

Explanation:

it was in my book I didn't searche'd it on internet

Answer 2

Answer:

It could either be as stubborn as mule(most prominently used) OR

As stubborn as a rock.

Because what matters is stubborn and a rock is way too stubborn.