A true zero point is a feature of which scale?

A true zero point is the defining feature of the ratio scale, where zero means the complete absence of the attribute.

This absolute zero allows meaningful ratios such as twice as heavy.

Nominal scale merely labels categories with no order or zero.

Interval scale has equal intervals but only an arbitrary zero, as in the Celsius scale.

Ordinal scale ranks cases without equal intervals or a true zero.

Weight, height and income are classic ratio variables.