Question

how do we know that the people of indus valley knew how to spin cotton​

Answer 1

From the discovery of many spindles and spindle whorls in the houses of Indus valley, it is evident that spinning of cotton and wool was very common. ... The purple dye on a piece of cotton has been taken to have been produced from the madder plant. Dyers' vats found on the site indicate that dyeing was practised.

Answer 2

Answer:

with meshine I think it is right