Why you add water to Sulphur dioxide and put a blue Litmus Paper in it why does it turns red

Because it produce weak acid and acid turns blue lithmus paper to red.

Explanation:

Sulphur dioxide SO2 react to added water to produce acidic product.

When sulphur dioxide react with water, it produce sulphurous acid H2SO3 which is a weak acid.

One of the properties of acid is that they turn blue lithmus papper to red, because the product is an acid, blue lithmus papper turns to red.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.