Science Homework Help!! ASAP! Why are alloys useful? ?

Alloys are useful because they have so many different uses and there are many different types. If you alloy pure iron with carbon you can create steel, which is much stronger and more useful than iron. There are also Shape Memory Alloys which when heated can change to a ceratin set shape. These can be used in braces, so that the brace gradually sets your teeth, rather than having to tighten the brace every few months.