Answer:
<em>Because the individual components of any mixture are not</em> <u>bonded</u> t<em>o each other, the composition of those components can vary. Also, some of the </em><u>physical</u> <em>properties of the individual components are still noticeable.</em>
Explanation:
A <em>mixture</em> is a combination of two or more pure substances that are present in any proportion and each pure substance keeps its own physical and chemical properties.
As oppossite to mixtures, the compounds are pure substances formed by two or more different elements which are chemically bonded to each other. So, while in the compounds the components (elements) are bonded in a fixed proportion, and their composition cannot vary, in the mixtures each component may be present in any proportion, which means that the <em>composition can vary</em>.
Take, for example, the simple case of talc and iron particles.This is <em>a mixture</em>. Talc is <u><em>not bonded</em></u> to the iron particles, and so their proportion, <em>the compositoin</em>, can vary in any form. Aslo, both talc and iron particles keep their own <u><em>physical properties</em></u>: you can perfectly separate the mixture by using a magnet to attract the iron particles, because they have not lost their magnetic property (a physical one).