When cream is separated from milk

the density of milk increases
the density of milk decreases
the density of milk remains unchanged
it becomes more viscous

The correct answer is: B. the density of milk decreases.

When cream is separated from milk, the milk becomes less dense because the cream is the part of the milk that is higher in fat and therefore has a higher density. The remaining milk is therefore lower in fat and has a lower density.

Option A is incorrect because the density of milk decreases when cream is separated.

Option C is incorrect because the density of milk decreases when cream is separated.

Option D is incorrect because the viscosity of milk does not change when cream is separated.