Which statement describes heterogeneous mixtures?

Heterogenous mixtures are those which are seperable by physical means. These mixtures do not have uniform properties throughout the substance. For example, blood is a heterogenous mixture because it can be seperated into its components via a physical change (centrifugation).

The Kelvin scale has no negatives on it.

Zero Kelvin is 'Absolute Zero', and nothing can get colder than that.