Which is a characteristic of mixtures?
(a) they are chemically bonded together.
(b) they can be classified as pure substances.
(c) they have fixed ratios between their components.
(d) they can be separated by physical processes.

The answer is:

(D) They can be separated by physical processes

Explanation:

A mixture is the combination of two or more different substances that are not chemically blend. So the forces that hold the constituents of a mixture are weak and each substance can be separated by physical methods. Example of this techniques are chromatography, distillation, evaporation and filtration.

The amount of each constituent in a mixture is not always the same, it can be in a less or in a greater quantity, thus it can be said that they are not present in a fixed radio.  

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.