A mixture requires a change; a compound requires a one.
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physical, chemical

Explanation:

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example:

Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present. Example: Air

The components of mixture do not react chemically and thus the constituents retain their chemical properties. Thus mixtures can be separtated by a physical change.

The components of compound lose their individual chemical properties. The components have to be separated by a chemical change.

i need mutiple choices

a:

by the combination of an unlimited number of elements