Step-by-step explanation:
An element is a distinct substance that cannot be split - up into simpler substances. Such substances consist of only one kind of atom.
From the list, the elements are:
helium
aluminum
A compound is substance composed of two or more kinds of atoms or elements joined together in a definite grouping. The properties of a compound are distinct and different from those of the individual elements that are combined in its make - up.
methane
water
Table sugar
A mixture is a substance made up of indefinite composition. The constituents reacts differently to changed conditions. They are easily separated into constituents by physical methods.
Vinegar
Steel
Milk